Geranium

Guidelines for Finishing High Quality Zonal and Ivy Geraniums
Karl Trellinger, Fischer USA
Assessment of current situation: early, in the middle, and at the end of the crop. It is very important to take the time and make a detailed assessment of all aspects of the crop. Determine where the crop currently is and where it ideally should be.
Make a list of all the changes that should be made for next year:
o varieties,
o timing,
o early Florel and Cycocel treatments,
o temperature,
o media, and
o fertilization.
Unfortunately, when you are reading this, the critical production time (the first five to six weeks after planting) for the big pot sizes is almost or completely over.
The ideal conditions for that first part of the crop are:
o 70°F day and night,
o 300 ppm feed, high soil moisture level,
o one to three applications of 350 ppm Florel depending on variety, vigor, and
o weekly applications of 750 ppm Cycocel on an "as needed" basis.
The idea is to promote branching, establish a strong root system, and at the same time to prevent big leaves, long petioles and overall stretchy plants. Ivies generally like three to four Florel treatments and a pinch four to five weeks after planting.
Florel should be applied two weeks after planting and then every 10 days as long as plants are actively growing.
If the new leaves are small and look dark green, Florel or Cycocel should not be applied until they are actively growing again. The lower the pH and bicarbonates of the water, the more effective Florel will be. Adding sulfuric acid to the water to drop the pH to 5.5 before adding Florel will increase its effectiveness. The soil should be moist and the application should be done in early morning, so the leaves can dry before the sun can burn them. To be on the safe side, Florel can be sprayed in the evening. Florel applications should be stopped six weeks before the sale. Afterwards Cycocel, or in warmer climates Cycocel - B-9 combinations or other stronger growth regulators, should be applied to keep the plants bushy and under control. Ideally, growth regulators should be applied in combination with negative DIF and cool morning strategies.
Envision the crop
Have a clear mental picture of the "perfect" geranium you want to produce. Based on the current plant structure, this mental picture will be extremely helpful for making the correct decisions at the right time, on a daily basis. At the same time, it is very important to envision the perfect plant depending on pot size, spacing and method of shipping. Keeping detailed notes about future adjustments for each variety, should bring you close to perfection in the years to come. Raise your perceived limits of how good your perfect crop can look, and you will be surprised and very proud of the outcome.
Attention to detail
Reading the plants on a daily basis and making the necessary adjustments of all the variables involved is crucial. The correct combination of temperature, humidity, light, soil moisture, feeding level, and growth regulation is a balancing act which has to be evaluated and corrected constantly.
Ideally, to achieve top quality geraniums, they should be pushed with 70 to 72°F day and night as well as high feeding, moisture and light levels. At the same time, they should be kept from stretching and "forced" to maximum branching and consequential flower power with growth regulators, cool morning drop, and "negative DIF" (day temperature is lower than night temperature).
Variety selection is extremely important and very often underestimated in its implications toward branching, early flowering, leaf size, flower power, space requirements, shattering, longevity, and overall beauty and shape of the flower. The quality of the variety, and not minor price differences, should be the determining factors when you purchase cuttings. For optimum performance, you need the best varieties for your specific needs. Once you have made the best possible selection, study each variety's individual traits to enhance its positive attributes and overcome its shortcomings. Selecting one variety or breeding line over another (depending on the specific attributes growers look for in a variety or breeding line) can save a considerable amount of money. Furthermore, grouping similar varieties together makes temperature and growth regulator management a lot easier.
Greenhouse Climate Management
Generally, it can be said that even under low light conditions, the temperature should not be lowered because it would result in growth reduction, impaired root development, and a higher chance of root and foliage diseases- the latter mainly caused by higher humidity. To grow a good crop with lower temperatures (particularly night temperatures) is definitely possible, but the same crop time will result in smaller, less branched plants. Particularly under low light (and consequently high humidity conditions) plenty of air movement and "heat and vent strategies" are extremely important for diseasecontrol. Another critical effect is sufficient transpiration, which is absolutely necessary for good growth and oedema management in ivies.
Temperature. The ideal temperature for optimum growth rate, habit, and flower formation is 70 to 72°F day and night. Depending on the pot size, this will be between five and 10 weeks. An average temperature of 68°F is good for a slower grown crop. The higher the day temperature compared to the night temperature ("positive DIF"), the more stretching of internodes and petioles, the bigger the leaves, and the more reduced the branching will be. Consequently, 72°F day and 65°F night (and even more so 75°F day and 61°F night) will save fuel, but will result in a more difficult-to-grow crop and in a less than ideal plant.
A "negative DIF" regimen can be started in the "finishing" part of the crop, which can be last three to seven weeks of the crop depending on the pot size. By keeping the night temperature at 70°F, the amount of "negative DIF"applied will determine both the growth- and stretch rate. A 62 to 65°F day would be the ideal range for compact growth.
The higher the "positive DIF" and the lower the light conditions, more growth regulating has to be done, especially under high-density conditions.
Cool morning drop can be started three to six weeks before the sale depending on pot size and growth rate. Dropping the temperature to 50°F starting at first light for two hours can strongly diminish the far-red light-induced stretching of the early morning hours and acclimate the plants to cold night temperatures in May- once the geraniums are planted. To further harden off the plants, the average temperature can be dropped a few degrees a few days before shipping, as long as there is enough air movement and no danger of Botrytis infection.
Light. Optimum light levels for zonals are 3,500 - 5,000 footcandles and 3,000 to 4,000 footcandles for ivies. Ivies hanging in the air above the benches, particularly in the second part of the crop, often receive too much light, heat, humidity, and extended periods of dryness.It is crucial to provide a sufficient water supply, ensure a good, well controlled and adjusted pH (5.3 to 5.6) and feeding schedule, avoid saucerless baskets, and group similar vigorous varieties together.
Humidity. Keeping the humidity low with sufficient airflow is the most important strategy in fighting Botrytis. High night temperatures as well as venting while heating are expensive, but very effective strategies for growing high quality geraniums. Ideally the humidity should be lower than 75 percent.
pH, Fertilization and Feeding Schedule
It is extremely important to constantly monitor and correct the pH to be at 5.3 to 5.7 for ivies and at 5.7 to 5.9 for zonals. Soil tests should be performed every two weeks, and the pH should be adjusted by using appropriate basic (calcium nitrate) or acidic (ammonium nitrate) fertilizers or sulfuric acid.
The salt level (EC) should be adjusted every two weeks and a complete soil analysis should be performed every four weeks. The readings four weeks after planting until the end of the crop should be: 250 ppm N, 30 ppm P, 350 ppm K, 150 ppm Ca, 70 ppm Mg, 50 ppm S, 2 ppm iron, 1 ppm manganese, 0.4 ppm zinc, 0.2 ppm copper, 0.4 ppm boron, 0.06 ppm molybdenum. A few clean water leaches before shipping will help reduce the chances of root damage if the plants dry out during shipping, in the store, or before the customer is able to plant them.
To prevent salt buildup, the feeding should be performed so 15 to 20 percent of the applied solution drips out of the pot. Different formulations have different effects on the soil pH and the softness of the plant. For example, 15-15-15 and 20-10-20 can be used for soft growth and for lowering pH, 15-10-30 for harder growth and slightly lowering pH, 15-5-15 with Ca and Mg for increasing the pH.
Depending on the soil analysis of micronutrients, Mg and Ca may have to be applied every fourth watering.
If any nutritional problems appear, a good recommendation is to leach the crop heavy with fertilizer solution ( When in doubt, leach out). Call for advice and get a soil analysis immediately.
If the EC (salt level) in the soil is high, don't let plants dry out and drench them with Subdue at one ounce per 100 gallon every four weeks.
If newly developing leaves become yellow under hot conditions, which usually first appears on certain ivy geranium varieties, drench with 3 to 4 ounce of Sequestrene 330 every two to three weeks in the early morning. The leaves should be rinsed off immediately after the treatment to avoid burning.
Feeding schedule. Ideally, geraniums should be grown on the dry side in the beginning. This will aid to the quicker establishment of a healthy root system. After that, they like to be evenly moist (not wet) for ideal performance.
Generally, geraniums should be watered after the plant's weight is half of the saturated weight, to ensure optimum plant development. Trying to keep geraniums compact by growing them "on the dry side" will slow down overall growth, reduce branching and decrease the overall flower power.
The feeding schedule has to be adjusted to changes in light, temperature, humidity, and plant age on a daily basis.
Dis-budding and Grooming
Dis-budding. To achieve the best possible branching and overall growth, it is very important to remove all the buds weekly, up to three to four weeks (depending on temperature and light conditions) before shipping. If buds are small, they can be pinched off if they are more mature, they should be removed at the stem-peduncle juncture, to avoid possible Botrytis infection sites. The dis-budding toward the end of the crop time should be staged such that, each variet's last dis-budding is done four weeks before shipping. This produces plants that are always "fresh" and ideally about 50 percent open. This ensures less shattering during the transport and enough flower power after planting. Another big advantage of weekly bud removal up to three to four weeks before the sale is that plants have a muchhigher bud and flower count. As an additional benefit, the flowers will develop in one flush.
Grooming. If you grow biggest pots (6.5-inch and up), five weeks before finishing is the best time to pinch out one or two dominant shoots that grow out of control in certain varieties. Removing old and dense foliage in the center of the plants will result in better light penetration into the plant. Consequently, there will be increased development of side shoots, less incidence of Botrytis, and a "cleaner" look at the time of sale.
Spacing
The ideal spacing will be determined by whether it makes more financial sense to produce a "top-notch" big (11 to 13-inch diameter), medium (8 to 10-inch diameter), or small (6 to 7 inch diameter) plant.Whatever the choice, the idea has to be to produce as many well branched plants as possible per square foot through proper use of growth regulators and temperature, without having them grow into each other. As the crop is being sold, ideally after flowering them out in different stages, the plants should be constantly spaced to get bigger, fuller, and hopefully more expensive plants. This also creates a more conducive buying environment, if the plants are sold out of the greenhouse.
Insects
It is absolutely mandatory to have a tight insect scouting program in place, so late insecticide applications can be completely avoided. Having to spray blooming plants can ruin a beautiful crop. Extra care must be taken to control thrips, because they also have to be controlled in the soil (DuraGuard works well as a drench). Spider and cyclamen mites (mainly on ivies) are especially challenging to detect early (Avid, Pentac, Thiodan, and Sanmite work well).
Diseases
The most important diseases to watch out for are: bacterial blight (wilt and spots), Pythium, Botrytis, geranium rust, and as well as Alternaria and Pseudomonas (mainly in the southern states).
Bacterial Blight or Xanthomonas campestris pv pelargonii can definitely be the most devastating disease.Besides ordering cuttings from a "clean" reputable source that goes through all of the culture virus indexing steps, as all major producers do, it is extremely important to provide and keep an absolute clean greenhouse environment (i.e.restrict visitors from other greenhouses, install foot baths, disinfect hands and knives between at least every bench). The best line of defense is to scan the crop weekly for any symptoms that look suspicious of the disease. Obtaining as many pictures from the disease as possible - in books, magazines, through extension services - will help immensely to properly identify the disease. The earlier Xanthomonas is detected, the better the chance to minimize the damage. Under some circumstances it is possible to avoid a catastrophe by early detection and the right course of action.
Suspicious looking plants should be sent to a reputable lab. Symptoms include: wilting plants or branches, small (1/15 to 1/8 inch), dark brown, "water-soaked" spots often on yellowish wedges between the veins, brown wedges between veins with the neighboring tissue becoming yellowish green, dark green veins shining through yellowish tissue, and upside curled edges of leaves often in conjunction with the appearance of wedges. If the result is positive, a second sample should be sent to a different lab for confirmation. At the same time, the supplier should be contacted and an action plan should be established about which plants should be discarded and in what manner, and how the greenhouses should be disinfected for next year's crop.
Pythium: Pythium can be avoided to a large extent by using coarse peat and not letting plants dry out particularly when salt levels are high (weekly pH and EC tests) and by not overwatering the plants. To be on the safe side, applying Subdue at 1 ounce per 100 gal every three to four weeks is an excellent way to minimize or eliminate Pythium problems.
Botrytis: Botrytis can be prevented with good air movement, cleaning, humidity below 75 percent (by raising the night temperature or "heat and vent" under rainy, damp conditions), and early morning watering. Combination sprays of two or three chemicals at the 50 percent or 33 percent rate respectively, work best against Botrytis. An excellent combination is Daconil +Chipco +Ornalin at 33 percent rate each. Ornalin should not be used on cuttings that are not rooted, because it might delay the rooting process. Zyban is another good combination product.
Geranium rust: As rust spores appear on the underside of the leaf, they easily can go undetected for quite a while, until the rust becomes hard to manage. Dithane (mancoceb) once a week at 24 ounce per 100 gallon prevents the onset and the spread of the disease. An excellent cure is Strike at 4 ounce per 100 gallon every week for three to four weeks in a row.
Scout the crop weekly for 0.1 to 0.2-inch yellow spots on the upper side of the leaf or the dark brown 0.1 to 0.2-inch big pustules (spores) on the under side of the leaves, to fight the disease early. In later stages, the dark brown pustules also appear on the upper side of the leaves and large concentric rings are forming on the underside of the leaf.
Alternaria: The fungal disease is more likely to be found in the warmer Southern climates and in geranium beds during rainy summers across the United States. The appearance is somewhat similar to Xanthomonas leaf spot, although the spots are more evenly distributed, have a more tan color, exhibit concentric rings in the later stages and there are no wilting wedges within the leaves. Chemicals that work against Botrytis, also work well against Alternaria.
Pseudomonas leaf spots: Pseudomonas cichorii (mainly in Florida) and Pseudomonas syringae (also in Northern climates) develop leaf spots that are generally larger than those from Xanthomonas. The diseases should be identified in a lab. Pseudomonas cichorii can also infect other ornamental crops.
Organization and Cleanliness "pay" off
The "Wow"-factor of a well organized, clean greenhouse, and overall facility cannot be emphasized enough. Nobody will doubt that a clean and orderly grocery store-particularly the fruit, vegetable and meat departments-is an absolute necessity for customers to "feel" good enough to purchase the products wholeheartedly. Because of a good, often subliminal perception, the customers value the products higher than the same products in an unorganized,unmaintained store. Similarly, customers and visitors will judge the image and value of the plants and your whole business according to their perception.
Aside from having fewer disease problems, it definitely "pays" to hire extra labor just to keep the whole facility clean and organized. If this is not done, the will current staff will probably not have enough time to take care of these important issues. Customers will put a higher value on plants that are clean and look healthy coming out of an environment that is organized and clean.
Greenhouses that provide their visitors and customers with a good buying experience know how important organization and cleanliness are for their success.
Detailed Care Instructions
Even the most beautiful geraniums are only "partially finished," until the customer is happy with their performance. They will promote the product and company by "word of mouth" and will likely return soon. A well written, detailed care instruction guide will reduce claims, cut explanatory time, and make customers feel cared for and much more comfortable with their purchases.
The care instruction guide should be perceived as the "geranium bible." It should be revised annually-which will prove your dedication to the customer. The instructions should be part of the sale and should include a description of the product you grow and sell, and why it is different and better as compared to other products. Proper care instructions should cover the specifics of the most frequent customer concerns.
The following topics should definitely be addressed:
o Immediate care (frost, light, water, storage, flower bud abortion)
o Extended care, depending on pot size (replanting, planting depth, disinfecting pots, soil amendments, drainage, light, water, fertilizer requirements, grooming, pest and weed control)
On a final note, finishing high quality geraniums is (as with all other plants) all about:
o commitment to excellence,
o attention to detail on
a daily basis,
o proper knowledge, and
o customer satisfaction.
The best indicator for success is the price tag on the plant matches the customers perceived value.
No endorsement is intended for products mentioned, not is criticism meant for products not mentioned.

 

 

Marketing Geraniums
Bridget Behe, Michigan State University
Geraniums have been one of the most popular bedding plants for several decades, and their popularity is likely to continue. The Season Sales Summary reports, conducted annually by the Bedding Plants International and GMPro magazine, show that geraniums are among the top five best selling bedding plants and have been for the last 20 years. Geraniums are colorful, and many grow well under a variety of conditions in a range of growing zones. Yet, as consumers become more sophisticated about how they buy many products, including geraniums, marketing strategies for these plants must also become more sophisticated. If not, you may lose some geranium sales to more creative marketers.
Research describing consumer preferences for flowers may provide some insight on which to base your geranium marketing strategy. The 1997 Season Sales Summary showed that 66 percent of the study participants grew geraniums from seed and 77 percent grew geraniums from cuttings. Pinto was the most popular seed geranium cultivar, reported by 36 percent of seed geranium growers; and Americana was the most popular vegetative geranium, reported by 23% percent of those growers. Many producers rely on red cultivars, but non-red colors are increasing in popularity in some markets.
There is some consumer research showing preferences for geranium flower colors. Wolnick (1983) showed that consumers in a Penn State study preferred red geraniums over other colors. Behe and others (1997) investigated geranium flower color preferences of consumers in five U.S. markets and found that flower color was the primary consideration in the purchase decision, followed by leaf variegation (zonal color) and price. Overall, red and lavender were the more preferred flower colors. White and pink were less preferred. For a given flower color, zonal and plain green leaves were preferred to leaves with white margins. As would be expected, lower prices were preferred to higher prices.
Your market may be more or less like the markets tested in these research projects. If you're just starting out, a product mix heavy in red cultivars is a likely place to start. Markets where gardeners have more experience or a higher level of gardening sophistication (they don't want what their neighbor has) will likely sell more non-red cultivars. Merchandising geraniums with other plants can help you market non-red colors as well. Consumers often buy what they know, or know they'll be successful with. Help them be successful by suggesting combinations for them to try, or by planting combinations in containers or display gardens. Provide the "recipe for success" so they don't have to guess about what might work in their own garden.
The research should give you some insight on where to begin to develop your marketing strategy. The next step is to understand your customers and their needs. Most consumers use bedding plants, geraniums included, to add color to their landscape. If your primary customers are homeowners, they may have needs different from a retailer with a different client base. A more urban retailer may have customers who have very little yard or gardening space, and container gardening may be more important. The landscape professional is another customer group that may purchase geraniums. Wholesalers will need to consider the unique demands of horticulture professionals in developing a marketing strategy for them. Whatever the customer base, you need to consider how the plants are being used by your clients. This will give you even more insight into a marketing strategy.
In the early part of the spring sales season, your clients may be interested in dispelling the winter dreariness right away. Many geraniums can tolerate some chilly temperatures, making them ideal for those spring "early birds" who want to add color spots around the front or back door. While flats and 4-inch containers may be most popular, consider adding value by planting some in decorative containers or offering a service where clients can have their containers filled with spring color (and suggest they come back for a summer planting!).
Hanging baskets make great sales and a big splash for a porch or balcony. But, think about converting or displaying some of those hanging baskets as tabletop planters. Show customers how to remove the hanger if they want to display it on the tabletop. Offer, through add-on merchandising, different ways to display those hanging baskets. Decorative hooks or chains will help lower the 12-inch standard hook wire to a more desirable display at eye level. You'll need to suggest these add-on sales before customers get geraniums home and realize the wire holds the planter up too high.
Later in the season, some clients may have forgotten to water their containers and may have a need to refresh the summer view. Geraniums are super to fill in areas of color where plants may have been lost. Many could be considered "self cleaning" because they readily shed petals after they have bloomed for several days. With the tremendous color selection, nearly everyone can find a color to blend with their color scheme. Be sure to display and use cultivar names, because this will help the consumer identify those plants that successfully grew in their own garden. Just as we learn the different apple cultivars that are good for eating and baking, you can help increase customers' awareness of geranium cultivar names that perform well for them or in their area.
Geraniums don't need to be just for springtime, either. In more moderate climates, they make ideal fall or even winter annuals. Uses are limited only by your imagination. "Show and tell" may work best as a sales and marketing tool when you make an effort to change how people use geraniums. If you plant them in and around the business, people will likely take your cue and sales can increase. If you display them on tabletops or with decorative chains and hangers, it creates a "I can do that too" attitude consumers will want to take home. Ask anyone with a display garden about sales of plants that look good in that garden; the plants almost walk right out the door.
Geraniums are popular and easy to grow for most consumers, whether novices or long-time horticultural professionals. New geranium species and cultivars offer a tremendous variety of scents and textures, in addition to the color they bring to the landscape. Add value to all geraniums you sell by helping customers be successful with their purchase. Give them a recipe for success by planting or suggesting geraniums in combination with other plants. Extend the sales period beyond the spring fling by showing how geraniums can, and do, perform well at other times of the year. Focus on the benefits geraniums provide to consumers, rather than the plants themselves, and your marketing strategy will be even more successful.
Literature Cited
Behe, Bridget, Robert Nelson, Susan Barton, Charles Hall, Steve Turner, and Charles Safley. 1997. Consumer Preferences for Geranium Flower Color, Leaf Variegation, and Price in Five U.S. Markets. HortSci.32:509.
Wolnick. D.J. 1983. Consumer preference studies with zonal geraniums. Flor. Rev. 162:31-33.

Systemic Acquired Resistance: Can it Take the Sting out of Geranium Bacterial Blight?
Steve Carver, Ohio Florists' Association; Harry Hoitink, Matthew Krause, and Tom DeCeuster, Ohio State University
Editor's Note: This article reports the initial results of work supported in part with a research grant from the Ohio Floriculture Foundation.
Want to scare the living daylights out of your geranium grower friends this post-Halloween season? Just whisper the words "Bacterial Blight" and watch the blood drain from their faces. If they have already faced the scourge, they may even start shaking and shrieking.
o The prospect of bacterial blight (Xanthomonas campestris pv. pelargonii - Xcp) in a geranium range is no laughing matter. There are a number of reasons for this, including:
o This disease-causing organism (pathogen) can enter a geranium range rather easily, even during normal greenhouse operations. Holding stock plants from year to year, bringing outdoor stock plants in during the fall, inadvertently bringing in infected material or contaminated media, and slacking on sanitary practices are just some of the ports of entry and persistence.
Once present, bacterial blight is readily spread to new plants during propagation and healthy surrounding plants during production.
The bacterium, Xcp, eventually becomes systemic within geraniums, moving through the water-conducting vessels in the stems, petioles, leaves, and sometimes the roots. Infected plants eventually die.
o Symptom expression is often minimal until later in production as temperatures become warm. By then, the significant production costs and effort that had been invested into the crop are lost. In some instances, symptoms may not develop until after the infected geraniums are shipped to other greenhouses or garden centers, compounding the problems and loss. Sometimes symptoms do not develop until after plants are growing in the landscape.
o There are no resistant varieties, and there is no effective chemical control. In effect, bacterial blight is a dreadful disease of geraniums.
For these reasons, there is zero tolerance for bacterial blight in the geranium greenhouse. If Xcp is found in the greenhouse (or even just suspected), growers will typically remove the affected plants and a significant number of apparently healthy plants around them to contain the problem. Growers can lose a critical portion or even their entire crop when an outbreak occurs.
But what if there was a way of inducing geraniums to "fight" (systemic acquired resistance or SAR) the infection. Is it possible to use beneficial microbes to induce SAR in geraniums to bacterial blight in a fashion similar to the way that the cowpox virus or dead/crippled polio viruses were used to induce resistance to smallpox and polio in humans? To be effective, the induced SAR would need to impart an elevated level of resistance to ensure a very high survival rate of infected plants and a minimization of symptom development (during warm weather as well as cool). Xcp would still be a principal problem that growers would continually strive to avoid. But its presence in the greenhouse would no longer spell disaster as it now does.
Since 1991, two new strategies have been adopted in several laboratories around the world with the ultimate goal of controlling this and other bacterial diseases. Beneficial bacteria and fungi supported in composed pine bark-amended mixes have controlled Xanthomonas diseases of radish, lettuce, and tomato in greenhouse tests by inducing systemic resistance in these plants. The second strategy is the application of bioactivators to the foliage of plants. These chemicals induce SAR in plants to fungal, bacterial and some virus diseases. Recent research at OSU has shown that a combination of these beneficial microbes and sprays with the new as yet unregistered chemicals are most effective for control of Xanthomonas bacterial spot of radish.
OSU/OARDC stepping-stones to our ultimate goal of controlling geranium bacterial blight are:
o Isolating and identifying beneficial microbes that will most effectively induce SAR in geranium against Xcp.
o Develop potting mixes, cutting dips, and seed treatments fortified with these biocontrol agents for control of bacterial blight in addition to other diseases caused by soilborne plant pathogens.
o Identify the best combination of microbial and foliar spray treatments for control of bacterial blight of geranium.
We have begun our work using Xanthomonas bacterial spot on a model crop with which we already have some experience - radish. The bacterial pathogen that causes the leaf spot, Xanthomonas campestris pv. armoraciae, is closely related to Xcp. We are now testing about 500 microbial isolations taken from the roots of radishes grown in media that statistically reduced disease symptoms. These organisms are being tested for their abilities to induce resistance in radish to leaf spot. The most effective microbial isolates for radish will then be tested for bacterial blight control in geranium. We recently developed a bioassay for begonias and will begin using it to screen for effective biocontrol agents and combinations in that crop.
A bioassay is currently being developed for geranium.
Our efforts to identify a system for inducing systemic acquired resistance to bacterial blight in geranium are still in the preliminary stages, but the prospects seem promising for developing such a system that together with sanitation and prevention can take the dread out of the words "bacterial blight."

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Ivy Geranium Production
John Erwin, University of Minnesota
The popularity of ivy geraniums continues to grow. Ivy geranium sales increased from 30.1 million in 1996 to 30.9 million dollars in 1997 (+3 percent). In Minnesota, ivy geranium sales increased 20 percent from 1996 to 1997. The increase of the ivy geranium sales is due, in part, to consumer and grower recognition of the relative heat and drought tolerance of this group of geraniums compared to other geranium types. In addition, breeding efforts have greatly increased the variety of colors and leaf shapes available in ivy geraniums and introduced new types with increased heat tolerance. This article outlines basic practices associated with growing ivy geranium stock, propagation of ivy geranium cuttings, and finishing an ivy geranium crop.
History. Ivy geraniums were first discovered in South Africa in the Cape Province and were first grown commercially in England in the 1700s. Initial breeding efforts in England resulted in the first semi-double and double flowering forms of ivy geraniums in 1875. The first seed propagated ivy geranium was produced in 1986 by Blair Winner of Denholm Seeds. Although there are seed propagated ivy geranium types available, most ivy geranium cultivars are propagated from cuttings (asexually). In total, cutting propagated ivy geraniums constitute approximately 20 percent of the geranium cutting market.
CULTIVARS AND CLASSES. There are four classes/groups of ivy geraniums:
Traditional Types -- These types have large, thick leaves with large semi-double or double flowers. Inflorescences are few but showy. Examples of this type include the cultivars Harvard, Yale, and Tavira.
Balcony Types -- These types originated from European breeding efforts; have small, thin leaves; numerous single flowers; branch profusely; and are more heat and drought tolerant than most ivy geraniums. Examples of this type include Balcons, Cascades and Decoras line.
Dwarf Types -- These types resemble the Balcony types except they are dwarfed (i.e., have a smaller plant form and flowers). An example of this type of ivy geranium is the cultivar Mini-Lila series.
Ivy Zonal Hybrids -- Leaves and flowers of these types resemble those of zonal geraniums but the plant has a vining habit. Flowers are fewer, and a semi-double to double. Examples of this type include the cultivars Pascal, Genchen, and Madeline Crozy.
STOCK PLANT PRODUCTION. The objective in stock plant production is to grow stock plants that produce as many high quality cuttings as possible per square foot per week. In order to achieve this, we need to receive plants early enough to build sufficient plant size, have a high rate of leaf unfolding during cutting production, have a high rate of photosynthesis and a low rate of respiration to increase cutting size/dry weight, and control stem elongation. Cutting dry weight is important because the weight of the cutting is often associated with good quality by the customer and the rootability of a cutting generally increases, and early cutting growth is better as cutting dry weight increases.
Plant Number Per Pot. In general, you should receive and pot rooted cuttings for stock plants use from December 1 to January 15. The earlier cuttings are potted, the more cuttings that plant will likely produce. Most growers plant three to five cuttings in a 10- to 12-inch hanging basket pot (without the hanger) for later sales. Alternatively, some growers pot rooted-cuttings in smaller pots (6- to 8-inch azalea pot) and transplant to larger containers later to minimize the space plants initially require.
Initial Pinch and Florel. Pinch cuttings or apply Florel after roots reach the edge of the pot (two to four weeks after potting) to induce early branching. Florel application should occur at the same time that you would pinch. Do not pinch or spray Florel too early as this can initially stunt plants. Spray Florel (350 ppm) on plants until foliage is wet in the morning on a cloudy day. Application of Florel on sunny, warm days at a higher rate (500 ppm) can cause leaf burn. Harvest cuttings from stock plants when a tip cuttings are 1.5 to 2.5 inches long and have a single, fully expanded leaf and a few small leaves. Repeat Florel applications on a monthly basis to stimulate continued branching.
Environment. Temperature has a direct effect on leaf unfolding rate, photosynthesis, respiration, and stem elongation. Photosynthesis is the process where dry weight is accumulated by harvesting light. Respiration is the process where dry weight is lost to maintain existing tissue. The rate that leaves unfold on a plant is dependent on the average daily temperature that an ivy geranium is grown. The warmer the average daily temperature, the higher the leaf unfolding rate, up to approximately a 76 to 86F average daily temperature. I have found the single most limiting factor in cutting yield with most ivy geranium propagators is insufficiently warm temperatures. Dry weight gain on plants increases as day temperature increases up to approximately 76F and as night temperature decreases to approximately 50F. However, we do not grow crops with a 76F day and a 50F night temperature, because such a temperature regime would increase stem elongation and reduce the average daily temperature, thus reducing leaf unfolding rate or yield. Instead, we grow at temperatures to maximize yield while achieving sufficient cutting dry weight and controlling stem elongation. Stem elongation, like dry weight gain, increases as the day temperature ivy geraniums are grown at increases relative to night temperature (the higher the DIF). Also, during a 24-hour period, stem elongation is most sensitive to temperature during the first part of the morning. Dropping temperatures early in the morning will reduce stem elongation. Conversely, increasing temperatures early in the morning will increase stem elongation. A good way to maintain leaf unfolding rate but reduce stem elongation is to drop the temperature early in the morning to approximately 50 to 55F to minimize stem elongation but not affect the average daily temperature significantly, therefore cutting yield. Based on the information presented above, stock plants should be grown with a warm average daily temperature to promote leaf unfolding. Stock plants should be grown with a day warmer than the night to promote dry weight gain. Stock plants should be grown with as little difference between day and night temperature as possible and with a cool morning drop in temperature to minimize stem elongation. I recommend a stock plant temperature regime of 70 to 74F day temperature, 64 to 68F night temperature and a cool morning drop (first three hours of the morning) in temperature to 58 to 60¡F to minimize stem elongation.
Light. Remember that there must be bright light (>200 umol m-2 s-1; or 1,000 footcandles) in addition to warm temperatures if photosynthesis is going to occur and result in good cutting dry weight. Low light conditions combined with warm temperatures will reduce cutting weight by reducing photosynthesis, increasing respiration, and reducing stem caliber and subsequent rooting. If light levels are low, either decrease temperatures to maintain cutting quality by reducing leaf unfolding rate and accept that your cutting yield will decrease, or increase light by turning on supplemental lighting (preferably high pressure sodium). Most growers will turn lights on (50 to 75 umol m-2 s-1; or 250 to 375 footcandles) at 5 p.m. and off at 2 a.m. each day to take advantage of off-peak rates.
Cutting Yield. Projected cutting yields per plant are as follows, if cuttings are planted on December 15 and recommended temperatures are used. Harvest one to two cuttings per plant on January 26. Harvest one to two cuttings per plant on February 9. Harvest two to three cuttings per plant on February 23. Harvest two to four cuttings per plant on March 8. Harvest three to six cuttings on March 22. Harvest three to six cuttings per plant on April 5 for late sales. After April 5, stock plants should be shaped immediately to allow baskets to finish for Mother's Day sales. In summary, you can harvest 12 to 23 cuttings per plant depending on the environment and cultivar.
Media. The ideal media for ivy geranium stock plants should have a pH of 5.5 to 6.2, be well drained/aerated, and have a high water and nutrient holding capacity. Since stock plants are grown for cuttings and then finished for sale, it is critical that plants be planted in a media that will maintain its structure until the following fall to insure good garden performance. For this reason, we recommend bark, coir, coarse peat, or rice hulls as amendments to a media to maintain porosity throughout the growing season. Media water holding capacity is increased compared to standard peat blends by adding rockwool, rice hulls, or sterilized soil. Nutrient holding capacity is increased compared to standard peat media by adding vermiculite, calcine clay, or sterilized soil. If rockwool or coir are added, test each material first to make sure that sodium, potassium, and overall soluble salt levels are not elevated. The best root development I have seen occurred when growing plants in coir-based media.
Fertility. Since ivy geranium stock plants are grown during low light/cooler temperature periods of the year, it's recommend using primarily nitrate-based fertilizers as opposed to ammonium- or urea-based fertilizers to avoid ammonium toxicity. Symptoms of ammonium toxicity include a reduction in growth, along with yellowing along the leaf edges. Media nutrient levels should be brought up to optimal levels as quickly as possible (Table 1). Therefore, it's recommend that you fertilize with 400 to 600 ppm nitrogen from a balanced fertilizer the first two to three you fertilize. After this, reduce ppm nitrogen to 100 to 200 ppm. You should make sure that stock plants also receive regular applications of calcium, magnesium, and micronutrients. All of these materials can be low or nonexistent in commercial fertilizer blends. If you are growing your stock plant crop in a humid environment (polyhouse with a non-concrete floor), the plant may not take up adequate amounts of micronutrients/calcium because the plant is not using very much water. As a result, the youngest leaves may turn yellow/white and become deformed because they are deficient in calcium or some micronutrient (often boron). Therefore, it's recommend you fertilize with a calcium nitrate-based balanced fertilizer and that you apply magnesium sulfate monthly along with additional micronutrients. In addition, if plants are not using much water, make sure you fertilize foliage periodically (overhead water) in the morning to foliar feed stock plants to insure that they have adequate calcium and micronutrients. Always do soil tests every two to four weeks. Most nutritional problems can be diagnosed using a soil test, however, tissue tests are valuable because they identify what the plant is actually taking up. Recommended media and tissue levels of nutrients are shown in Table 1. Additional nutritional information can be found in the "Most Common Problems" section in this article.
CUTTING ROOTING. Harvest cuttings first thing in the morning to insure cuttings are turgid (have as much water in them as possible). Dip/talc cutting ends of difficult to root cultivars in an IBA talc (Homodin #1) prior to "sticking" cuttings to encourage rooting. Many ivy geranium cultivars will root freely and not require an IBA application. Cuttings are typically rooted in a deep-celled plug tray. Root cuttings in a soilless media that contains a polymer if rooted cuttings will be shipped in the tray to minimize breakage during the shipping process. If cuttings will not be shipped, most commercial soilless media are satisfactory for rooting. Mist cuttings frequently during the first four days (approximately 10 to 15 seconds every 15 minutes). Reduce misting frequency to once or twice every day. Media temperature should be maintained at 75 to 77F. Media pH should be between 5.5 to 6.0. It may be necessary to amend the water to maintain media pH during the rooting period and fertilize cuttings after they root with a weak nitrate-based fertilizer (100 to 150 ppm N-P-K). See the section below on how much acid to add to water to minimize the impact of irrigation water alkalinity on media pH. Rooting starts within two weeks. Complete rooting will take three to five weeks. For maximum cutting rooting and branching after cuttings are planted in the finished container, apply 200 ppm Florel to cuttings one week before planting.
FINISHING IVY GERANIUMS. Traditionally, ivy geraniums are sold in hanging baskets. However, alternative uses for ivy geraniums, such as mixed baskets, window boxes or ground covers, have greatly expanded the potential sales of this crop. Therefore, growers are experimenting with growing ivy geraniums in packs, 4-inch, 6-inch, and 8-inch pots as well as baskets. Recommendations below are based on hanging basket-produced ivy geraniums but apply, in most cases, to other finished products as well.
Planting. Plant four to five rooted cuttings per hanging basket. Plant one to two cuttings in the center and three cuttings 2.5 inches from the edge of the pot. Plant five to seven cuttings in a 12-inch pot/basket. Plant two to three cuttings in the center of the pot and three to four cuttings 2.5 inches from the edge of the pot. Specimen baskets should be started the beginning of February. Compact baskets should be started the end of February. If three and five cuttings are used for the 10- and 12-inch pots, respectively, start plants an additional three to four weeks earlier. Alternatively, if more than the recommended cutting numbers are used, plants can be started later. If selling ivy geraniums as a 4-inch potted crop, pot rooted cuttings in mid-March and apply Florel, rather than pinching, to promote branching. If selling ivy geraniums as a 6-inch crop, pot two cuttings per pot in the beginning of February to March depending on the final size of the desired product.
Media. Ideal media for ivy geraniums should have a pH of 5.5 to 6.0, be well drained/aerated, and have a high water and nutrient holding capacity. The optimal pH for ivy geraniums is below that for seed geraniums. Do not grow seed geraniums at pHs below 6.0 as manganese/iron toxicity will occur.
pH. Media pH generally is 5.0 to 6.0 when it arrives. After a crop is planted, media pH generally changes. In what way media pH changes depends on the components in the media, the water alkalinity, and the makeup of the fertilizer. Pine bark in the media tends to decrease media pH. In contrast, coarse lime in the media tends to increase media pH over time. The most common factor that affects media pH is the irrigation water. Irrigation water often contains carbonates that will increase media pH over time. A measure of the amount of carbonates in water is the alkalinity of the water expressed in milliequivalents or ppm of calcium carbonate. If your water alkalinity is high, you essentially are adding a significant amount of lime to your media every time you water. Minimize the impact of irrigation water on media pH by adding acid to the water to neutralize the alkalinity. How much acid you need to add depends on the alkalinity of your water and the acid that you want to use. In general, it's recommend decreasing water alkalinity to 100 to 120 meq using sulfuric acid. Water alkalinity in the United States varies from 70 to 550 meq. The exact amounts of acid needed for your water can be calculated from Table 2 or by calling your state Extension specialist. Fertilizer also affects media pH. In general, fertilizers that have nitrogen in the ammonium nitrate or urea form tend to decrease media pH. In contrast, fertilizers that have nitrogen in the nitrate form tend to increase media pH. Whether a fertilizer is acidic (will reduce pH) or basic (will increase pH) can be assessed by looking at the fertilizer bag. In most cases there will be a term "acidity" or "basicity" on the bag. Acidity refers to the pounds of calcium carbonate limestone required to neutralize the acidity caused by applying one ton of the specified fertilizer. The basicity of a fertilizer identifies how many pounds of calcium carbonate limestone that the application of one ton of the specified fertilizer is equivalent to. These terms have little relevance to us except that they give us some indication of how acidic or basic a fertilizer is. In general, fertilizers more than 400 acidity or basicity will have a significant and rapid impact on a media pH. The closer the acidity or basicity is to zero, the less of an effect that the fertilizer will have on your media. Some acidity and basicity levels for common fertilizers are shown in Table 3.
Nutrition. Nutrient levels should be increased initially to the recommended levels as quickly as possible. Too often, media nutrient levels are below recommended levels early in production when proper nutrition is critical. For this reason, I recommend fertilizing ivy geraniums with 400 to 600 ppm N (nitrogen) from a balanced fertilizer early in production (first two to three fertilizations) to bring nutrient levels up to the recommended levels. We also recommend fertilizing with every watering. Nitrogen levels can often be reduced to 150 to 250 ppm after this to maintain nutrient levels in the desired range. Always base how much you fertilize on your soil tests, which you should conduct every two to four weeks. Also remember that the fertility within a pot will vary with the grower. Each grower differs in how they water and will, therefore, apply different amounts of fertilizer to a pot. In northern climates, it is critical to fertilize with fertilizers that have the nitrogen in the nitrate form during cool temperature/low light periods of the year (i.e., February and early March). The amount of ammonium nitrate/urea in a fertilizer can increase as the season progresses from winter to spring. In general, itÕs recommended fertilizing with a "high nitrate" fertilizer during January and February (15-0-15 Dark Weather Feed), an Excel based fertilizer (15-0-15 Cal-Mag) during March and a Peat-Lite type fertilizer during April and May (20-10-20). Although I've have had good experience with these materials, there appears to be some alternative fertilizers that we will look at this season including the Greencare fertilizers. Suggested media and tissue nutrient levels are shown in Table 1. pH affects the availability of nutrients to the plant. High media pH will "tie up" iron, manganese, boron, and phosphorus in the media. In other words, you can have adequate nutrient levels in the media but the plant will express a deficiency symptom because those nutrients are not available to the plant. In contrast, low pH will "tie up" calcium and magnesium. For this reason you should, as recommended before, conduct regular soil tests to maintain pH between 5.5 and 6.0.
Last Pinch. The last pinch should occur no later than four to six weeks prior to the anticipated sales date. Remember, in most cases, an application of Florel can substitute for a pinch. Apply Florel at 350 ppm on a cloudy day to minimize the possibility of foliage damage. Also remember that there is considerable variation in the response of different cultivars to a Florel application.
Temperature. Goals to have when establishing the environment for an ivy geranium crop include rapid development, numerous flowers, and compact growth. To achieve rapid development, growers must maintain minimal average daily temperatures. As was mentioned, the rate at which a plant develops increases as the average daily temperature a plant is grown at increases to approximately 76 to 80F. Flower number on ivy geraniums is also dependent on the average daily temperature plants are grown. Ivy geranium flower number per inflorescence increases as the temperature plants are grown at decreases to approximately 50F. For instance, flower number per inflorescence decreased from 9 to 3.8 flowers on the cultivar 'Nicole' as average daily temperature increased from 54 to 84F. As with managing stock plants, you should try to minimize the difference between day and night temperature to minimize stem elongation. This can be difficult since ivy geraniums are traditionally hung high in the greenhouse where day temperatures are warmest and night temperatures can be cool. Therefore, maintain baskets on the benches for as long as possible and apply Florel to promote compact early growth and apply light applications of Cycocel (500 to 750 ppm) later in production to control stem elongation. Based on the above relationships, I recommend growing ivy geraniums with a 68 to 72F day temperature and a 58 to 63F night temperature with a cool morning drop in temperature to 50 to 55F.
Light. Ivy geraniums vary in their light requirements. In many cases, they are exposed to more light in a greenhouse than is optimal for growth. Excessively high light levels will decrease growth possibly by increasing temperature. In general, ivy geraniums prefer light levels between 2,500 to 3, 500 footcandles (500 to 700 umol m-2 s-1). Cultivars vary somewhat in their light preference with 'Sugar Baby' preferring approximately 2,000 footcandles and 'Amythest', 'Cornell', and 'Pascal' preferring 3,000 to 4,000 footcandles.
Diseases. There are four diseases that attack ivy geraniums: Botrytis, Rust, Rhizoctonia, and Pythium. Botrytis is a foliar fungal disease that will establish itself on damaged tissue first and then on living tissue. Botrytis spores can only germinate when they are on a wet surface for an extended period of time (four to six hours). Two cultural ways to control Botrytis are to remove dead or damaged leaves from the plants, benches, and below the benches to remove the spore source; and water plants in the morning only and reduce humidity to maintain dry foliage to inhibit Botrytis spore germination.
Rust is caused by the fungus Puccinia pelargonii zonalis. Symptoms appear first as small circular yellow spots on the undersides of the leaves that develop and increase in size and get a brown spot in the center. Avoid your chances of Rust by not carrying plants over, reducing overhead watering, and do not take cuttings from plants that have been grown outside.
Rhizoctonia and Pythium are fungal diseases that attack primarily the roots. Rhizoctonia can attack the stem/leaves when conditions are very wet. Pythium is a water mold, therefore requiring wet/moist conditions to proliferate. Rhizoctonia tends to proliferate most in warm weather, and Phythium tends to proliferate most in cool, moist conditions. Culturally manage these diseases by not overwatering plants. Chemically manage these diseases by drenching monthly with fungicides alternating between a Subdue+Cleary's 3336 or a Banrot application.
Insects. There are few insects that infest ivy geraniums. Thrips are probably the most problematic lately. The most obvious symptoms of thrip infestation are white/necrotic streaks on the flower petals/foliage. Since thrips are so difficult to control late in production, take extra time to control them early in production. Apply Azatin+Mavrik, Duraguard, Talstar+ Orthene, Tame or Sanmite to control thrips. Remember to rotate among three families and spray every five days for a minimum of four times in a row. Red spider mites can also be a problem in ivy geranium production. The most obvious symptoms of red spider mite infestation are necrotic spots on the foliage and webbing around the shoot tips. Control red spider mites by applying Avid, Pentac, or Sanmite. Apply to the entire plant making sure that the underside of the foliage is sprayed. Spray every five days. Repeat treatments for a minimum of four spray applications (about three weeks).
Postharvest. Limitations for continued performance of ivy geraniums once they leave the greenhouse are petal shattering immediately after shipping, drying out plants, and insufficient fertilization. Flowers can shatter or fall off plants after shipping. To avoid flower shattering you can spray silver thiosulfate (STS) two weeks prior to shipping. SILVER THIOSULPHATE IS NOT REGISTERED FOR USE ON IVY GERANIUMS. The best way to alleviate possible nutrient deficiencies once the geraniums leave your care is to educate the consumer to fertilize regularly and to apply a slow release fertilizer when the plants are sold. Apply a tablespoon of Osmocote (14-14-14) to the surface of the media when plants are sold to provide some nutrition to plants after they leave the greenhouse.
MOST COMMON PROBLEMS.
Iron deficiency. The symptom of iron deficiency is interveinal chlorosis (yellowing between the veins) on leaves near the shoot tip. Iron deficiency is caused by insufficient iron in the media or high media pH. If you have high media pH (>7.0) decrease pH by applying 3.5 ounces 85 percent phosphoric acid per 100 gallons of water or 1.8 ounces of sulfuric acid AS A ONE TIME APPLICATION. This amount will generally decrease media pH by 0.5 pH units. If necessary, reapply acid after conducting a soil test. Overhead watering with a fertilizer that contains iron is a quick and easy way to temporarily alleviate this problem.
Magnesium deficiency. A symptom of magnesium deficiency is interveinal chlorosis on leaves near the bottom of the stem. Low pH or insufficient magnesium in the media causes magnesium deficiency. Increase pH by leaching with water with a high alkalinity or with a basic fertilizer. If magnesium levels are low in the media, drench with 8 ounces magnesium sulfate (Epsom salts) per 100 gallons of water. In most cases, it is helpful to do a monthly drench of Epsom salts as a preventative since many fertilizers do not contain magnesium.
High Soluble Salts. Symptoms of high soluble salts include burning of the leaf edges on lower leaves, burning of root tips, slight wilting on sunny days even when the media is moist, and a general slowing of growth. Solve by leaching media with clear water for 10 to 20 minutes. Prevent this problem in the future by either leaching slightly every time you water or conducting periodic leaches. Regardless, the easiest way to avoid this problem is to monitor your media soluble salt levels to insure that they do not get too high (Table 1).
Excessive Stem Elongation. Stem elongation varies with cultivar. Excessive stem elongation occurs when the difference between the day and night temperature is high or when no growth retardants are applied to plants. Solve this problem by reducing day temperatures, dropping temperatures the first three to four hours of the morning, or applying Cycocel at a rate of 750 ppm or 1 to 4 ppm Bonzi. Cycocel may have to be applied weekly. Do not spray more that 750 ppm Cycocel as leaf edge burning can occur. Regardless if you use Cycocel or Bonzi, apply these materials early in the morning when the material will stay wet on the foliage for an extended period. Florel application will also decrease stem elongation but cannot be applied during the last six weeks of production.
Odema. Odema is a physiological disorder believed to be caused by fluctuations in temperature, humidity, and water status. Solutions to this problem include maintaining a constant growing environment, maintaining a pH between 5.5 to 6.0, maintaining relative humidity below 75 percent, and feeding with fertilizers with nitrogen in the nitrate-based forms. Irrigate only in the morning.
No/Few Flowers. Lack of flowering is usually caused by high temperature, late application of Florel, or overwatering/water stress. Temperatures should not exceed 76 to 80¡F, if possible. In most cases, an inflorescence will form but the number of flowers in that inflorescence will be greatly reduced. Florel should not be applied during the last six weeks of the production cycle.
Botrytis. Botrytis (grey mold) can be a problem when conditions are humid, plants are dense, and plants are watered late in the day.
Table 1. Media and tissue standards for ivy geranium (Pelargonium peltatum) production in a soilless mediu. Tissue test standards are in percentage data except where noted.
Nutrient Media Spurway Saturated Past Tissue Levels (%)
pH 5.5-6.0 5.5-6.0
Soluble Salts 120-180 2.0-4.0
Nitrate 150-180 100-199 3.4-4.4
Ammonium 2-8 2-10
Phosphorus 5-10 10-15 0.4-0.7
Potassium 50-60 150-250 2.8-4.7
Calcium 120-180 200-300 0.9-1.4
Magnesium 40-60 50-125 0.4-0.6
Iron 0.25-0.50 0.3-3.0 115-270 ppm
Manganese 0.25-0.50 0.3-3.0 40-175 ppm
Zinc 0.25-0.50 0.3-3.0 10-45 ppm
Boron 0.25-0.50 0.1-0.5 30-100 ppm
Copper N/A 0.1-0.5 5-15 ppm

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"Once Upon A Time": The Development of New Geraniums
Richard Craig, Penn State University
Two flower growers needed a scarlet flowered geranium for their market. One chose a cultivar named 'Scarlet Ribbons' and the other chose a cultivar designated as 'Buckeye'. Both purchased young plants as plugs, grew them according to standard cultural practices, and marketed them to their respective customers in 4.5-inch plastic pots. Neither grower experienced serious nutritional or pest problems; their cultivars were self-branching without pinching; and crop time and space requirements were virtually identical. When they compared the economics both crops yielded similar profits. Both growers were so delighted that they were more than willing to tell friends that their cultivar was the best scarlet flowered geranium in the world. One of their mutual friends, let us call him Dennis, was puzzled by these endorsements; how can each cultivar be the best in the world? He mused that there had to be some difference between these cultivars, a point that was left unchallenged by his grower friends. Dennis was correct in his appraisal; there were actually many differences between these cultivars. 'Scarlet Ribbons' is a cutting propagated cultivar produced in a clean stock program which includes both culture-indexing for Xanthomonas and virus-indexing protocols. It is protected by a United States Plant Patent, but it was developed in Germany. The grower paid a royalty for each cutting; this royalty was paid to the plant breeder to support his ongoing cultivar development program; the grower also paid a supplement to support the propagator's clean stock system. Conversely, 'Buckeye' is a seed-propagated cultivar that is produced as an F1 hybrid. An F1 hybrid is legally defined as a cross-pollination between two true-breeding parents. 'Buckeye' was bred in California, but the seeds were produced in Costa Rica. The plugs were grown in Michigan and the young plants were brokered by a New York firm. F1's are not patented; however, the parents are protected under "trade secret" laws since they are proprietary to the breeder. However, the breeder still must support his research program, and seed production costs must be recovered; thus the price for each seed/plug/young plant must include these pseudo-royalties. Are these two cultivars just "variations on a theme," as is the case with many horticultural/agricultural cultivars, or are there other substantial genetic or physiological factors which differentiated them? For an answer to this question, perhaps we should focus on the ancestry of zonal geraniums. Once upon a time, actually about 1632, the first geranium relative, Pelargonium triste, was transported by John Tradescant from South Africa to England. The shipment was made by The Dutch East India Chartered Company whose trade routes used the Cape of Good Hope in South Africa as a stopover in the journey between Europe and India. In the ensuing years, dozens of Pelargonium species also made their way to the greenhouses and conservatories of Europe. All zonal geraniums resulted from the hybridization of Pelargonium inquinans and Pelargonium zonale, two of these South African species. This hybrid was first reported in 1732 by Johan Jakob Dillenius, a German born, English botanist. Ultimately, it was named Pelargonium xhortorum. In the following 150 years a "breeding frenzy" erupted, and thousands of hybrids were produced from this original cross by early plant fanciers. Why were the European plant enthusiasts so enamored by these "African" imports? What made these particular plants special? Were they more colorful, more tolerant of environmental stresses, or were they easier to grow? How did they differ from all of the other Pelargonium species? One genetic fact that could be used to describe these 18th century zonal geraniums was that their parents had 18 chromosomes. In plant breeding parlance, they are called diploids Ð a term used to describe plants that have one pair of each of the basic chromosomes that characterize the species. Chromosomes are linear arrangements of DNA; the genes that control each and every plant trait including compact growth, early flowering, and pest resistance reside on the chromosomes. Everything remained normal with these primordial zonal geraniums until 1880, when a spontaneous mutation occurred which resulted in a doubling of the basic chromosome number. This event produced cells, which produced tissues, which differentiated into organs, and ultimately into whole plants with 36 chromosomes. Thus, the mutant plants had four of each chromosome and were called tetraploids. Each gene in these plants was now represented as four doses rather than the normal two doses. These mutants had plant parts that were slightly larger and slightly thicker and with more substance than the corresponding diploids. This mutation was so impressive that breeders concentrated on further developing these new types almost exclusively for the next 80 years. Most modern, commercial, asexually propagated cultivars are tetraploids. Asexual propagation of tetraploids is necessary since these cultivars cannot normally be produced true-to-type from seed. In other words, seed from these plants will produce a mixture of progeny. Also, fewer seeds can generally be produced on tetraploids based on their lower fertility. Because they are asexually propagated they can be patented. Therefore, the propagation, use, and sale of plants and even plant parts is prohibited except with the permission (license) of the inventor. Prior to 1980 only 24 cultivars were patented, but hundreds of tetraploid cultivars have been patented since 1980. What caused this explosion of new cultivars? This leads us to the rest of our story. Remember that the original species parents of zonal geraniums were diploids with 18 chromosomes. If one produced seed of the parental species, the progeny were virtually identical to the parent plants. This property of diploids, although not universal, can be achieved through continued self-pollination. Diploid types are genetically less complex than tetraploids and true breeding lines are easily developed. In the early 1960s, researchers at Penn State University took advantage of this diploid condition and introduced 'Nittany Lion', the first commercial seed-propagated zonal geranium. Once a breeder has true breeding lines, it is a simple extension to produce F1 hybrids. The first commercial F1 hybrid geraniums were developed by the Joseph Harris Seed Company and the PanAmerican Seed Company. Almost all seed propagated geraniums are diploids and today they represent about 50 percent of all geranium sales in the United States. It is interesting to note that even with the advent of seed-propagated cultivars, cutting types have continued to increase in sales. It was the competitive force of seed-propagated geraniums that spawned the greater emphasis on breeding improved tetraploid cultivars. The grower has a myriad of cultivars to consider when implementing a marketing program. They can choose all tetraploid-cutting propagated types, all diploid-seedling cultivars, or both. There are dozens of exciting flower colors, various leaf colors and sizes, and vigorous or compact growth habits to choose from. Thus 'Scarlet Ribbons' and 'Buckeye' are indeed very different, yet they are very much the same -- just ask the two flower growers. Although some people believe that tetraploids or diploids are inherently better greenhouse or garden plants, there is no scientific evidence to support such a conclusion. In my experience, both groups include cultivars which can be successfully produced for specific markets.

Raising A Cultivated Geranium
Ellen Talmage, Talmage Farm
We could all use a little cultivation in our lives...this is especially true for your geranium crop. How you care for your geranium throughout the crop year will determine its quality. Every grower would like to get top dollar for his or her crop, but only those growing top quality will get it. To become one of the "elite," a geranium must have fine breeding and culture to fetch that high price. To grow a quality geranium you must get inside its head and think like a geranium. What motivates that mysterious creature called Pelargonium hortorum (zonal geranium)? A geranium is much like a person when it comes to many of its needs. For top performance, a geranium needs the following conditions to flourish:
Light. The geranium is a high light plant. Without it, it will become depressed. A zonal geranium needs between 3,500 to 4,500 footcandles to stay perky, while an ivy geranium (the eternal optimist) require less, between 2,500 to 3,500 footcandles. Growers stuff their greenhouses full of plants and don't sit back to consider the impact of overcrowding. The greenhouse offers the only source of light for your geranium. Try to avoid growing plants on top of your geraniums or they may be victimized by hanging baskets. You know the type, dripping all over the foliage of other plants causing freestanding water. It's the root of many pathological evils.
Space. Just imagine yourself attending a wonderful elegant party. You are all dressed up in your Sunday best, have plenty to eat and drink, you are warm enough, and your light level is satisfactory. If the room is too crowded you will have a hard time enjoying yourself. It's a real concern in schools and prisons, why not in greenhouses? A grower who stuffs his or her greenhouse is certainly not doing a service to any of the crops being raised. Plants cannot be packed too tight or rebellion will be unavoidable. Signs of unrest include the stretching of internodes, yellowing and dropping of bottom leaves, and the spread of diseases such a botrytis. Always be thinking ahead as to where and when you'll want to space your geraniums. The majority of the time and money have been invested in the crop within several weeks of the finish time. Don't mess things up now.
Growing Media. The geranium is a finicky creature that likes to be planted in quality real estate. Paying attention to the soil requirements throughout the growing process is well worth the effort. When propagating cuttings, remember to have a media that has high porosity so that callused or unrooted cuttings will be easy to stick. Oasis and other soiless media are fine provided they never dry out. If a peat-lite mix is used, make sure to have the pH at or around 5.8. The mix should have high porosity containing a high percentage of perlite or other ingredients that provide the air space needed. When planting a rooted cutting for finishing, the peat-lite growing media should meet these requirements: pH between 5.8 to 6.3, contain long peat fiber, have good aeration (not packed down too tight when filling the pots), and be moist at the time of planting. A geranium must be wined and dined properly if you expect exceptional quality. During the rooting process for cuttings, no feed should be given until the third or fourth week into the process. At this time a weak solution (half rate) can be applied. When the rooted cutting is mature enough to be stepped up into its final container, a constant feed of +/- 200 ppm is appropriate after the roots have reached the sides of the pot. This should happen within four to seven days in a 4.5-inch pot and up to 10 days in a 6-inch pot or larger. A geranium plant seeks consistency. It needs to feel it will receive fertilizer and water evenly. A geranium does not take well to first starving and then drowning. When a geranium is upset with its grower because of poor feeding practices it will tell you. A hungry geranium will turn yellow and growth will be stalled. But beware of the overfed geranium, it will show self-destructive behavior by burning its own roots and then show the signs of a hungry plant. Check fertilizer injectors regularly to guard against the problem of inconsistent feeding. A good leaching every third or fourth watering is a geranium's best therapy, and do tests to monitor salts.
Temperature. Try to maintain a night temperature 63 to 68F and a day temperature of 75 to 80F. Again, this will reaffirm your commitment to the insecure geranium.
Height Control. Now that the geranium has you, the grower, just where it wants you, be prepared for a little unruliness. It is normal for an adolescent geranium (oh, excuse me, it now wants to be called 'Pelargonium') to want to find out its limits. It will try to stretch as tall as it can without giving any consider- ation for its branching responsibilities. Ever hear the saying "time to nip it in the bud"? Pinching is a disciplinary action that some growers like to take. Yes, you get the point across, but at what cost? You may end up slowing the finish time by two to three weeks. Remember, these are teenagers and you want them out of the greenhouse as fast as possible. Why not try the kinder gentler way of discipline -- growth regulators? Look for telltale signs to take action. If you, as a grower, feel your Pelargonium is heading into a growth spurt, be ready to act. Your growth regulator program may be made of several products, including Cycocel, B-Nine, and Bonzi. Be respectful of the impact these growth regulators have on your Pelargonium. There is something called too much of a good thing. When the discipline is right, you will feel more comfortable with the process.
Diseases and Pests. It is never too soon to warn your Pelargonium about the problems they may be exposed to out there in the gardening world. Hopefully it will end up nobly displayed in a poolside planter at a posh estate and not dumped in the trash behind a big-box store. All you can do is stress sanitary practices. If you keep a clean greenhouse, you will teach by example the way a geranium should live out its life. Doing a self-exam with a sticky card once a week is recommended by entomologists everywhere. Give Pelargonium plenty of ventilation so it can fight off Botryis, just as you, the grower fend off colds by providing yourself with plenty of rest and vitamin C. It is your duty as a horticulturist to inspect your Pelargonium, especially around the roots. White healthy roots indicate a geranium with high self-esteem. If you fear there is some kind of problem, don't procrastinate. Take steps to identify whatever problems come up and act quickly. Your whole family of geraniums may depend on it.
Timing and Specifications for Quality Timing. is something you must do from the heart. Only the grower knows for sure, but here are some guidelines for planning purposes. Finished 4.5-inch pots should take six to eight weeks from rooted cuttings. Each plant should have a minimum of one fully opened bloom and be heavily branched. Six-inch pots should take 9 to 11 weeks from rooted cuttings. Each plant should have at least two fully opened flowers and be heavily branched. Eight-inch pots should take 14 weeks or longer from rooted cuttings. Each plant should be loaded with fully opened blooms and be heavily branched. Finishing time is dependent on your market and growing environment. Growing unconventional sizes may be just the right niche for you. Remember that these are only guidelines.
Keep a Scrapbook. Before you know it, that little cutting will callus, root, and finish. Shipping Pelargonium is a bittersweet experience for any grower. Shutting that rollup door on your delivery truck knowing Pelargonium is going out into the gardening world can bring a tear to the eye (not to mention money in the pocket). It is common for you to ask, "Did I do everything I could to insure the best culture for Pelargonium?" By keeping records, you can be sure of it. A grower can go back to any part of the crop year to review the methods and improve upon them for the next year. You should be proud that a top quality Pelargonium was produced from your greenhouse and your overflowing wallet will reconfirm that fact.

Diseases of Geraniums
Stephen Nameth, The Ohio State University
Introduction. Zonal geraniums (Pelargonium x hortorum) are one of the most commonly grown bedding plants in the world. Their large, bright, showy flowers make them prized by professional and home gardeners everywhere. One of the most common problems associated with the growing of geraniums in the greenhouse is the identification and control of pathogens that cause geranium diseases. Geraniums are susceptible to some of the most common and destructive diseases associated with the production of greenhouse bedding plants. The following describes some of the important diseases of geraniums, as well as basic identification, management, and control strategies for these diseases in a greenhouse setting. The pathogens which cause diseases in geranium are fungi (the most common), bacteria (the potential to be the most destructive), and viruses (common, but in most cases not economically important). Many of the geranium pathogens discussed in this article can also cause disease in other greenhouse bedding plants (wide host range); however, some of the pathogens discussed will only affect geranium (host specific). This host specificity, or lack of it, plays an important role in the control of the disease in question.
The Diseases.
Gray Mold or Botrytis Blight of Geranium. Gray mold or Botrytris blight is caused by the fungus Botrytis cinerea. It is a common fungus with a very wide host range. Most greenhouse-grown bedding plants are affected by this fungal pathogen. Symptoms of this disease include flower blights, bud rots, leaf spots and leaf blight, stem canker, cutting rot, and damping-off of seedlings. The disease is most destructive under conditions of high relative humidity (at or above 85 percent), and cool temperatures. Under these conditions the fungus can be seen growing and sporulating on the infected tissue. Fungal growth is characterized by patches of fluffy, gray/brown fungal strands (mycelium). These mycelial patches or infected areas produce a cloud of spores if they are touched or disturbed by air currents. Infected tissue is soft and brown, and sometimes appears water-soaked. With flower and bud blights, the disease first appears as a brown discoloration or spot and later the flower or infected bud becomes rotten and water-soaked. Geranium leafs affected with gray mold develop a brown triangular leaf lesion, which starts at the margin of the leaf and moves inward. The fungus may continue to colonize the leaf, grow down the petiole, and under ideal conditions, infect, produce a lesion, and girdle the stem. There are many approaches to the control and/or management of gray mold in the greenhouse. First and foremost, it is important to control the environment in an effort to make it unsuitable for the fungus to grow and sporulate. Keeping the relative humidity below 85 percent and not allowing any water to stand on the plant surfaces for extended periods of time will go a long way toward the control of this pathogen. Whenever possible, plants packed closely together should be spread apart to allow for better air circulation. Horizontal fans should be used to provide good air movement above and within the plant canopy. Spores can also gain access through wounds. Cutting stubs are very susceptible to gray mold infection. Plants with wounds should be protected with a fungicide, as the wound is the perfect environment for the fungus to initiate the infection process. Sanitation is also key in the control of this disease. Dead and dying leaves along with spent flowers should be removed from the plant and discarded. Infected plant material should be removed from the greenhouse so that it is not a source of inoculum for the rest of the greenhouse. In cases where gray mold is at epidemic proportions, fungicide applications will be necessary for adequate control. There is a wide variety of fungicides that will offer good control of gray mold in the greenhouse. Products such as ClearyÕs 3336, Domain, (Thiophanate-methyl), Exotherm Termil, Daconil 2787, Daconil Ultrex (Chlorothalonil), Phyton-27, Kocide 101, (Copper-based compounds), and Chipco 26019, (Iprodione) are all labeled for this disease. These products should be used in combination with the above mentioned cultural controls strategies as part of an integrated disease management program. Alternating fungicides of different types will help reduce the possibility of pathogen resistance.
Bacterial Wilt of Geranium. Of all the diseases of geranium, bacterial wilt has the potential to be the most economically devastating. This disease has the potential to move rapidly through the greenhouse, infecting every geranium in its path. Bacterial Wilt is caused by the bacterium Xanthomonas campestris pv. pelargonii (Xcp). Though Xcp is primarily a pathogen of zonal geraniums, Bacterial Wilt can also affect seed, ivy, Regal, perennial, and scented geraniums. The most characteristic symptom associated with Xcp infection of geraniums is a systemic wilt of the leaf. In most cases the leaf petiole remains turgid, thus giving the effect of an Òumbrella.Ó This symptom is very diagnostic. Other symptoms include yellow to brown v-shaped lesions on the leaves starting from the margins inward, tiny brown water-soaked leaf spots, and in advanced cases black stem lesions, which under conditions of high humidity may have yellowish droplets of bacteria oozing from cracks in the lesion. The best method of controlling Bacterial Wilt is to not allow the Xcp or Xcp-infected plant material into the greenhouse (exclusion). Since there is nothing Xcp- infected geraniums can be treated with to ÒcureÓ them of the infection, and since the bacteria can be transmitted through infected, yet nonsymptomatic vegetative cuttings, excluding Xcp from the production site is the first and best line of defense. Purchasing culture-indexed geraniums from a reputable producer who will stand behind the quality of their product is critical to getting started on the right foot. If you do not purchase culture-indexed material from a reputable producer, you will be asking for a problem. Do not carry over stock geranium material from one year to the next. Allow for a geranium-free period in your greenhouse each year. This will help eliminate the possibility that any Xcp is being carried over from year to year. Once a Xcp-free production area has been established, it is imperative that it remain that way. Do not mix new material from different sources in with disease-free material until it has been determined that the new material is also disease-free. It is also important that a strict sanitation policy be established. Treat this disease as a hospital would treat any highly infectious disease. Restrict access to the stock production area by not allowing personnel involved in the finished product free access to the stock production area. Teach your employees to recognize the symptoms of bacterial wilt, so that if the disease does appear they will be able to identify it before it has the opportunity to spread. If Xcp is detected, remove the affected material at once. If there is any doubt, have the affected material tested. Most reputable university-based or private testing laboratories will be able to let you know within a day or two if your suspected plant is clean or not. Plants adjacent to or from the same source may also need to be tested or at least removed and isolated. They may also be infected but may not be showing symptoms. Nonsymptomatic, infected geraniums can continue to be a source of infection if not identified. Do not grow ivy geraniums above zonals or other susceptible species because the ivy geraniums commonly do not show symptoms when infected; however water dripping down or splashing from these plants can be a source of infection to the plants below or in the immediate vicinity. Though there are no known chemical controls for bacterial wilt, copper-based compounds such as Phyton-27 and Kocide 101 may have the potential to slow down the spread of Xcp. Xcp-infested propagation tools and work surfaces should be thoroughly disinfested with Greenshield, Physan 20, or a 10 percent bleach solution. Since the Xcp pathogen is not seed transmitted, growing seed geraniums is another possible way of keeping this destructive disease out of the greenhouse.
Damping-Off, Root Rot, and Black Leg. All three of these diseases are caused by the fungus Pythium sp. They are closely related as far as the environmental conditions that favor disease development. Damping-off is a common disease associated with geranium seedlings. Under conditions of cool media temperatures (less than 50F) and excess moisture, the fungus will attack the roots and crown (base of the seedling) of the seedling. Affected seedlings collapse onto the media under their own weight. In advanced cases the fungus can be seen growing on top of the media and will move from seedling to seedling in the closely spaced plug tray. Root rot usually attacks the plant in the later stages of development. Initial symptoms will be wilting of the plant, particularly in times of moisture stress. Close observation of the affected plant roots will reveal dark brown lesions on or at the tips of the roots. If left unchecked these lesions will spread, cause death to the entire root, and move up the stem. Black leg is primarily a disease associated with cuttings and young plants. Symptoms of black leg first appear as black lesions at the base of the cutting or stem, and under ideal conditions this lesion will continue to develop up the stem. Usually black leg is an indication of advanced root rot. Eventually the cutting or small plant will wilt and collapse, resulting in death of the plant. Control of all three of these diseases starts with growing seedling and cuttings at the proper temperatures and using a media that is well drained that will not allow for water saturation over extended periods of time. Rooting media should be free from all pathogens. Using steam to sterilize the media or starting off with a commercially produced, sterile rooting media may be necessary. Surfaces or tools that come in contact with the cuttings should be cleaned and disinfested with a sanitizing agent, such as Greenshield, Physan 20, or a 10 percent solution of bleach. To minimize root rot problems, use a well-drained medium and avoid over-watering. If the disease is found, fungicide drenches with labeled compounds such as Subdue MAXX, Banrot, and Truban will be effective.
Rust. Leaf rust of geraniums caused by the fungus Puccini pelargonii-zonalis is another disease that has the potential to be economically devastating to geraniums. Symptoms associated with rust disease begin as small, yellow spots on the underside of the leaf surface. These spots eventually turn a rusty brown color and develop into a mass of rusty spores. On the top of the leaf surface there are yellow spots that correspond to the rust spots below. In the absence of the proper controls, these rusty spore masses continue to expand and form target-like spots. The disease will cause severe leaf deformation and premature leaf drop. Conditions that favor the development of this disease are a greenhouse environment that will allow for the development of free moisture on the leaf. The rust spores, which can spread from plant to plant in the air and in splashing water, need free water on the leaf surface in order to germinate and penetrate the leaf. This disease can spread very quickly, so strict attention should be payed to the identification of rust as quickly as possible. If rust is seen on one plant in a shipment of cuttings, the whole shipment should be rejected. To help eliminate this disease in the greenhouse, overhead watering should be avoided. Enough spacing should be between plants to allow for adequate air flow around plants. This will cut down on the possibility of high humidity in the plant canopy and the subsequent formation of water droplets on the leaf surface. There are many fungicides labeled for the control of leaf rust on geranium. Most of these have to be applied at weekly intervals in order to achieve adequate control. There also is a wide variety of geranium resistance to this disease. Some geranium varieties appear to be less susceptible to rust than others, and these varieties should be considered if rust has been a problem.
Southern Bacterial Blight. Southern Bacterial Blight of geraniums, caused by the bacterium Pseudomonas solanacearum, is primarily a problem in warmer climate production areas. The initial symptoms are the wilting and death of the lower leafs of the infected plant. The stem of the plant will eventually turn black and the geranium will collapse in death. Environmental conditions that favor this disease are high temperatures, 75 to 100F, and plant surface wetness. If possible, avoid overhead watering and high temperatures. Copper-containing compounds, such as Phyton-27 and Kocide 101, may help slow down the spread of the disease. Growing geraniums from seed and using only culture-indexed cuttings will help eliminate the possibility of acquiring this destructive pathogen.
Virus Diseases. Geranium is the host of a variety of plant viruses, most of which do not have the potential to cause serious economic damage to the host. Unlike diseases induced by fungi and bacteria, virus-induced diseases are much more difficult to diagnose and control. The two most destructive greenhouse viruses, impatiens necrotic spot virus and tomato spotted wilt virus, are not a serious problem in geraniums. Common symptoms associated with virus-infected geraniums include yellow leaf spots, yellow ring spots, leaf crinkle or curl, mosaic pattern, color break in the flowers, and overall yellowing and stunting. Sometimes the symptoms may appear and disappear depending upon the environment and the growth stage of the geranium. This does not mean that the plant is no longer infected, it only means the conditions are not favorable for symptom expression. Plants infected with viruses will continue to grow and develop into a sellable product. Plants infected with viruses should not be used for propagation material, as the virus will be carried from the mother plant to the cutting. Culture-indexed geraniums should be used for propagation material. Insects such as whiteflies, thrips, and aphids can move viruses from plant to plant and should be maintained at low levels. Most of the geranium diseases discussed in this article can be avoided by only growing geraniums that have their origin in stock material that has been through an extensive culture indexing for disease by the producer. Purchasing culture-indexed material is the best way to get the growing experience off on the right foot. From that point, an integrated disease management program should be initiated. This program should involve the use of cultural and chemical controls. In some cases, if cultural controls are strictly followed, chemical controls will not be necessary.

Geranium Pest Management
Raymond Cloyd, Purdue University
Geraniums are one of the most popular floricultural crops grown in the United States. The common types grown in greenhouses are Regal geraniums (Pelargonium x domesticum), zonal geraniums (Pelargonium x hortorum), and ivy geraniums (Pelargonium x peltatum). Similar to other greenhouse-grown crops, geraniums are attacked by a wide-variety of arthropod pests. The primary pests of geraniums are aphids, whiteflies, spider mites, fungus gnats, and thrips. Damage caused by these organisms can reduce the aesthetic quality and salability of greenhouse-grown geraniums.
Aphids. The primary species of aphids that attack geraniums are the green peach aphid (Myzus persicae), the potato aphid (Macrosiphum euphorbiae), and the geranium aphid (Acyrthosiphon malvae). All aphids have cornicles (tubes) on their abdomens. Aphids feed by inserting their piercing-sucking mouthparts into the vascular tissues and removing plant sap. They generally feed on young terminal growth and on leaf undersides. Aphid feeding causes plant stunting, wilting, and leaf yellowing. Aphids also excrete large amounts of honeydew, a clear sticky liquid that serves as a medium for black sooty mold fungi. In addition, when aphids molt, they leave behind white caste (molting) skins. Both honeydew and molting skins can reduce the aesthetic quality of a crop. Aphids reproduce very rapidly within a short period of time, which is why populations seem to explode overnight. Aphids generally start off as random clumps, but as populations increase in size winged adults are produced which allows aphids to move to other parts of the greenhouse. Aphids can reproduce without mating (parthenogenesis). Each female can give birth to 100 to 150 live female offspring. These females, in turn, produce their own offspring in 7 to 10 days. The advantage of this type of reproduction is that females can produce offspring without having to waste time searching for males. Because aphids reproduce at high rates, it is important to rotate chemical classes to prevent pesticide resistance.
Whiteflies. The common whitefly species that attack geraniums are the greenhouse whitefly (Trialeurodes vaporariorum) and the silver-leaf whitefly (Bemisia argentifolii). The ideal way to tell the difference between the two species is by examining the pupae stage. Greenhouse whitefly pupae are perpendicular to the leaf surface with setae (hairs) around the outer edge. They resemble a cake on the leaf surface. Silver-leaf whitefly pupae lay flat on the leaf surface and have no setae. They appear as bumps on the leaf surface. The adult stage can also be used to differentiate between the two whitefly species, but this is not as reliable as the pupal stage. In addition, adults fly around when disturbed which may make identification difficult. Adult greenhouse whiteflies hold their wings flat over the body, whereas silver-leaf whiteflies hold the wings roof-like at a 45 degree angle. Whiteflies damage plants by withdrawing plant sap with their piercing-sucking mouthparts. This causes plants to appear chlorotic, yellow, and stunted. Similar to aphids, whiteflies also produce large amounts of honeydew. The whitefly life cycle consists of an egg, four nymphal stages, a pupae stage, and an adult. A generation takes approximately 30 days. Developmental time is shorter under high temperatures. Adult females can live between 25 to 40 days and lay 150 to 200 eggs. Eggs are generally laid in a circle on leaf undersides. These eggs hatch into young crawlers that move around before settling down to feed on plant sap. Almost all whitefly life stages are located on leaf undersides. It is important to determine which life stages are present, because some life stages are more susceptible to pesticides than others. Eggs and pupae are more resistant to pesticides than nymphs and adults. Growers that identify the life stages accordingly will be able to time insecticide applications for maximum effectiveness. In addition, thorough coverage of leaf undersides is essential, especially when plants have a dense canopy. If possible, space plants to increase canopy penetration with spray applications.
Spider Mites. Two-spotted spider mite (Tetranychus urticae) can be a problem on geraniums, especially ivy geraniums. The two-spotted spider mite is yellow-green to dark green with two dark spots on both sides of the body. They are generally located on leaf undersides. Spider mites cause injury by removing chlorophyll (green pigment) from leaves with their needle-like mouthparts. This can result in leaf yellowing, leaf bronzing, necrotic leaf margins, and mottled bleach foliage. The spider mite life cycle consists of an egg, larvae, nymphs, and an adult. Females can lay between 50 to 200 eggs during their lifetime. High temperatures and low relative humidities favor spider mite development. For example, spider mites can go from egg to adult in approximately 11 days at temperatures between 80 and 90F. Spider mites can quickly move within a geranium crop when plants are spaced close together. They can also be moved throughout a greenhouse by air currents or workers handling plants.
Fungus Gnats. Fungus gnats are a common problem early in geranium production. This is because the adults are highly attracted to fresh growing medium. Adults are poor fliers and are generally located near the medium surface. They can be identified by the Y-shape in each wing. Adults generally don't damage plants directly, as they are primarily a nuisance. However, Pythium and Botrytis spores can be attached to the adult body. When adult fungus gnats land on plants these spores can drop off, and if the proper environmental conditions are present these spores can germinate and possibly start an infection. The fungus gnat life cycle consists of an egg stage, four larvae, a pupa, and an adult. Adult females lay eggs in the growing medium. Females can deposit between 100 to 200 eggs in the cracks and crevices of the medium surface. Eggs hatch into white, transparent, legless larvae with a black head. The larvae damage plants by directly feeding on small roots and root hairs. Their feeding can provide entry sites for soil-borne pathogens. Larvae can also tunnel into geranium stems. The larvae can be a serious problem before plants develop a well-established root system. In addition, larvae can transmit fungal pathogens such as Pythium and Thielaviopsis. Larvae are generally located within the top 2 inches of the medium surface. However, they can be found deeper in the medium profile, even at the bottom of pots. Environmental conditions that favor fungus gnat development are high humidity and cloudy, cool days with slow evaporation. When growing medium and areas under benches remain moist, this leads to increased fungal growth which promotes fungus gnat development. This is one reason why growers should allow the growing medium to dry out between waterings. The growing medium may also influence fungus gnat development. Composted bark or peat-based mixes may promote more fungus gnats. Coir (coconut husk fibers), when used as a growing medium, does not have any inhibitory effect on fungus gnats.
Thrips. Thrips (i.e., Western flower thrips, Frankliniella occidentalis) can be a problem on many species of geraniums; however, they are especially troublesome on ivy geraniums. Thrips can damage geraniums by feeding on foliage and flowers. Thrips feed on plant fluids using their piercing-sucking mouthparts. The injury they cause to leaves resembles oedema. Because of their size, thrips can enter unopened flower buds and cause early flower abortion. Flowers that do open may have scarred petals, which can reduce plant salability. The thrips life cycle consists of an egg stage, two larval stages, two pupal stages, and an adult. Similar to the other greenhouse pests, thrips developmental time is shorter under high temperatures. In general, the lifecycle from egg to adult takes two to three weeks. However, at temperatures between 80 to 85F the lifecycle can be completed in 7 to 13 days. Females can live from 30 to 45 days and lay between 150 to 300 eggs during their lifetime. Because thrips are so small (less than 2 mm), they can easily enter greenhouses through doors, vents, and sidewalls. Distribution fans used to prevent diseases can move thrips throughout a greenhouse. In addition, thrips can be carried in on plant material. It is important to ascertain which thrips life stages are present because certain stages can tolerant pesticides more so than other stages. Eggs and pupae are resistant to most pesticides, whereas the larvae and adults are more susceptible. Also, rotating pesticide classes will alleviate the possibility of thrips populations developing resistance.
MANAGEMENT.
Scouting. Scouting is the key component in a geranium pest management program. Scouting allows growers to quickly detect pest numbers early and determine which pest management strategies are effective. Scouting for pests within a geranium crop can be done using colored (i.e., yellow or blue) sticky cards and performing visual inspections. An effective scouting program is dependent on consistently checking for pests on a regular basis and maintaining accurate records. Target scouting strategies based on pests attacking geraniums. Use sticky cards for adult whiteflies, thrips, and fungus gnats. Also, sticky card placement is important. Place sticky cards vertically just above the crop canopy. Placing sticky cards horizontally within the plant canopy on pot edges or on the growing medium can monitor fungus gnats. In addition, place sticky cards near doors, sidewalls, and vents to detect pest populations (i.e., thrips) that are migrating into the greenhouse from the outside. Visual inspection of foliage can be used to detect the presence of spider mites, immature thrips, whitefly nymphs, and non-winged aphids. Placing 1/4-inch wide sliced potato wedges on top of the growing medium can also monitor fungus gnat populations. Allow the wedges to sit for 72 hours then turn them over and check for fungus gnat larvae.
Weed Management. Removing weeds from inside and outside greenhouses can prevent pest problems. Weeds inside the greenhouse serve as hiding places for pests, while weeds outside are sources of pests which can migrate inside when geraniums are brought into the greenhouse. There are herbicides registered for use inside greenhouses, but they should be used with extreme caution and when the greenhouse is empty. Herbicides can also be used to control weeds outside the greenhouse. However, use extreme caution when applying these materials, especially near vents and sidewalls. In addition, remove weeds from pots, especially old stock plants or "pet" plants. When pulling weeds by hand, donÕt leave weeds inside the greenhouse, because when the weeds dry up pests can move onto geraniums already present. For more information on herbicides registered for use inside greenhouses consult the publication, "Tips on Managing Floriculture Crop Problems." This publication is available from the Ohio Florists' Association.
Sanitation. Removing plant and medium debris can eliminate sources of pest problems. Plant debris can harbor thrips, spider mites, whiteflies, and aphids. Discarding plant debris from benches and floors prevents pests from moving from dried material to geraniums in the greenhouse. Place all plant debris in plastic bags or in sealed containers. Avoid aggressively disturbing plant debris, because this can cause pests to move off the old debris onto your geraniums. After placing all debris in a plastic bag or sealed container remove it from the greenhouse. Old growing medium can provide sources for fungus gnats and thrips to pupate. Removing all old growing medium can help growers prevent outbreaks of these pests. Managing algae on floors and benches can prevent problems with fungus gnats. Avoid excess moisture from accumulating by watering plants only when they require it, fixing leaks in irrigation systems and cooling pad distribution tubes, and shutting off hoses after watering. Disinfectants such as sodium hypochlorite (bleach) and quaternary ammonium chloride salts (Greenshield¨, Physan 20¨, and Triathlon¨) can be used to remove existing algae from floors and benches.
Plant Inspection. Inspecting geraniums before they are brought into a greenhouse can prevent pest problems. Inspect plants when they are brought into a greenhouse, or place geraniums into a holding area. Place several yellow sticky cards among the crop to determine which pests are present. Also, inspect leaf undersides for the presence of spider mites and whitefly nymphs.
Chemicals. Many pesticides are currently registered for controlling pests attacking geraniums. However, the effectiveness of pesticides is contingent on their proper use. The following guidelines will help growers maximize pesticide efficacy and possibly lead to reduced pesticide applications: Properly identify the pest(s); Use the proper pesticide for the pest(s) you are dealing with; Read the pesticide label prior to making any application. Use required label rates. Using more than the label rate can cause phytotoxicity. Using less than the label rate can result in poor pest control. If there is a range of rates (i.e., 6 to 10 oz/100 gals) consult your county extension agent or contact a product technical representative to determine the appropriate rate for your particular situation; Apply the pesticide with the proper application equipment/formulation type; Use pesticides that are less than three years old. Pesticides that are exposed to extremes in hot and cold temperatures for an extended period of time may have lost their effectiveness; Time pesticide applications when the most susceptible life stage(s) of a pest is present. This will enhance the efficacy of the pesticide; Thorough, uniform coverage is essential to obtain maximum effectiveness with a pesticide; Rotate pesticide classes when appropriate to avoid selecting for resistant individuals in the pest(s) population; Space plants to increase the effectiveness of a spray application; Scout the crop following a pesticide application to evaluate how well it performed. Be aware that spray applications can disturb pests, which may lead to high counts on sticky cards suggesting that the population is increasing.
Biological. Biological control in geranium production involves the use of parasitoids, predators, beneficial nematodes, and entomopathogenic fungi to control pests. Biological control can be successfully implemented as long as growers are committed to the program. Entomopathogenic fungi (i.e., Naturalis-O and Botanigard) are used in a manner similar to pesticides so they can be applied with some conventional spray equipment. However, they must be applied before pest populations reach excessive levels. Consult the product label for more information regarding use of entomopathogenic fungi to control pests. The following guidelines are for using parasitoids, predators, and beneficial nematodes. These guidelines will assist growers in using biological control in their greenhouse operation to manage geranium pests: Read as much as possible on how to use biological control; Start on a small scale; Consult supplier catalogs for use and release rates of available biological control agents; Find a reliable supplier and make all orders well in advance (i.e., two weeks); Avoid spraying pesticides with "high" impact on biological control agents four weeks prior to releasing biological control agents. Generally, materials with "low" impact on biological control agents, such as entomopathogenic fungi, may be used before making initial releases; Check biological control agents prior to release to be sure they are alive; Release the proper biological control agent; Release biological control agents immediately upon delivery. Delaying release reduces effectiveness; Make releases of biological control agents in the morning or late evening. Never release during the warmest part of the day; Release biological control agents before pest populations are "high." Don't release biological control agents when pest populations are rampent. Biological control is a preventive approach to pest management and not a curative method to quickly reduce pest numbers; Scout the crop regularly to evaluate the performance of the biological control program and determine when additional releases are necessary. For more information on how to use biological control in greenhouses, consult your county extension agent or biological control supplier.
References. 1. Geraniums IV. 1993. J. W. White [ed]. Ball Publishing, Geneva, Illinois. 2. Seed-Propagated Geraniums and Regal Geraniums. 1992. A. M. Armitage and M. Kaczperski. Timber Press, Portland, Oregon.

Marketing Geraniums
Peter Konjoian, Konjoian's Floriculture Education Services
Volumes have been written over recent years about new crops and the excitement they have brought to our businesses. Articles on supertunias, osteospermum, double and New Guinea impatiens, scaveola, and helichrysum have graced these pages and those of every other trade publication. But when it comes right down to it, most of us are still growing and selling more geraniums during the spring than any of these other crops. Marketing geraniums once was as easy as planting a cutting or seed, watering and fertilizing it as it grew, and then putting it on a bench in the sales area or loading it on a truck for wholesale delivery. Life is not that simple these days, and marketing this crop now requires more skill than ever.
Zonal or Seed. Twenty years ago there was a great debate on the subject of whether zonal geraniums or seed geraniums were better. This debate has subsided during the past decade as growers and garden center operators begin to understand the advantages and disadvantages of each type. Marketing either effectively requires playing up each type's strengths and uses. Productive breeding programs have generated an abundance of choices for flower color, plant size, and outdoor performance. Ivy geraniums have also benefited from breeding work and are easier to grow both in the greenhouse and in the garden. It wasn't long ago that if someone mentioned this crop at a conference the cultural condition of oedema would quickly become a part of the discussion. Our knowledge of moisture management, nutrition, and environmental control has come close to eliminating this problem from the greenhouse completely. In particular, the European or Alpine types have played a significant role in the increased popularity of ivy geraniums. These cultivars have vigor and garden performance that are excellent.
Product Offerings. How many sizes of geraniums do you offer? If your answer is one, namely a 4-inch pot, then you are probably missing the boat. With the assortment of containers now available, it is relatively easy to carve a niche in any crop just by growing it in a different container than the competition. Even though the backbone of my program is a 4.5-inch seed geranium, it's the larger and smaller sizes that generate more profit on a square foot basis. Think of different container sizes much like diversifying a stock portfolio. However, don't lose sight of the fact that the 4.5-inch pot compensates for lower square foot profit by its shear volume. Included in our geranium product mix are pot sizes larger than 4 inches such as 6 and 8 inches. Both zonal and seed cultivars are grown in these larger pots, and even though they require more production space, the higher retail price makes the effort worthwhile. One zonal cutting is planted per 6-inch pot and two per 8-inch pot. For seedlings, two are planted per 6-inch pot and three per 8-inch pot. The larger pots are used as doorstep plants that can be placed or planted into decorative containers. Some are planted directly into the ground to provide that instant garden for customers with early season decoration needs, such as graduation parties and wedding receptions. Smaller sizes are often the most profitable units of any crop, as the density of production on a square foot basis far exceeds that of larger containers. My favorite "small" container is a 306 unit where individual cell size is comparable to a 3.5-inch pot. Three of these six packs fit in a standard 1020 flat and each has a convenient plastic handle. I grow seed cultivars in this unit, as they are compact and make a handsome product when sold with one open flower and buds showing on each plant. They are grown beside packs of bedding plants in relatively inexpensive greenhouses and don't need to be grown on benches in more expensive growing environments. If zonal cultivars are produced in this tight spacing, be sure to select more compact cultivars in order to keep quality as high as possible. Vigorous cultivars will require some type of growth regulation to control plant size while in the packs.
Quantity Discounts. My 4.5-inch geraniums are priced with a quantity discount. Retail signage should read something like the following: Geraniums $3.69 each, 10 or more $3.29 each. Retailing experts tell us that this pricing format allows the consumer to see the savings clearly, without having to do any math. It is clear that once the tenth plant is selected, a price savings of 40 cents per plant is realized. Contrast the above pricing strategy to the following; Geraniums $3.69 each, 10 for $33. While the price is the same, the consumer is forced to calculate the per plant cost in order to realize the discount. The customer must either multiply $3.69 by 10 to determine what the price would be without the discount or divide the $33 by 10 to determine how much is being saved per plant. Another line could be added to this sign: "Save 40 cents per plant," but there is now one less line for other information, and the most effective signs are those that are simple and to the point. A line such as "still our favorite plant for sun" is too powerful a message to have to leave off the sign because of lack of space. Another cumbersome feature of this second sign is what happens when 12 plants are purchased. Now the cashier needs to do the math or have a table by the register with precalculated totals. On a busy day in May the last thing needed is another table on the cashier's price list. Usually, as the container size increases the need to offer a discount decreases. High ticket items are not usually purchased in large numbers, so offering a quantity discount may be frustrating to customers who only need one. If large geranium baskets carry a $49 retail price, offering a 10 or more discount isnÕt going to appeal to many customers. One might say that the customer who is interested in 10 hanging baskets has enough discretionary income that it's not price, but other factors, that enter into the purchasing decision. Being able to get 10 matching baskets, delivery of the bulky items, or being able to custom order specific colors mixed together may be much more important to this customer than a discount on the selling price. Meanwhile, the customer purchasing a single basket may ask why he or she is being penalized for only purchasing one. If a discount is preferred with larger containers then the quantity should be lowered. For instance, if geraniums are offered in 8-inch pots as patio plants or the "instant garden" concept, then offer a quantity break point that is realistic. Buying 10 or more may not appeal to most customers, whereas offering a discount at five or more might be very attractive. If you can encourage the customer to start thinking, "Well, I only need three, one for each step...but, if I buy two more then I save $1 per plant...I'll put one of them by the pool and I can throw the other in the rock garden by the garage," you have accomplished two things. First, your customer feels good about the purchase having realized a significant savings on a per plant basis. Second, you just sold two more large geranium pots. In order to make these marketing strategies work, where "work" means generate profit for your business, pricing must be set carefully and thoughtfully. If production area is limited, one might argue that quantity discounts are not the answer because increasing the quantity grown is not feasible. In this situation the basic economic law of supply and demand comes into play. If production space, and hence supply, are limited then demand is going to exceed supply and price discounting is not called for. To the contrary, in this scenario a price increase is warranted because supply is tight. One must try to get a feel for what percentage of a crop is sold at the individual plant price compared to what percentage is sold at the discounted price. For most small operations without the benefits of barcoding and computerized inventory control, this comes down to the gut feeling of the person manning the checkout lines. I have learned to interrogate my father thoroughly during the spring rush because in his comment "everybody's buying the 10 or more specials," his idea of what "everybody" means and my interpretation are usually very different. It's usually my mom who steps in to mediate and tell me that my father's use of "everybody" simply means that he is very happy with the way the day went. She's right. Whenever it rains my dad's comment goes from using "everybody" to "nobody." By the way, if everyone is indeed buying at the 10 or more price, then you probably have set the discounted price too low. Don't be afraid to work that law of supply and demand in your business. Remember, our products are merchandise just like thousands of other products. Time-tested business rules apply to us as well as to greeting cards, movies, or furniture. If you determine that the bulk of the crop is going to sell at the discounted price, be sure to do enough homework to assure that this price is generating the profit you desire. Estimate what your average selling price is. If your best guess is that 75 percent of the plants sold for the quantity discount price of $3.29 and 25 percent sold for the full price of $3.69, then the average selling price was $3.39 ($3.29 x .75 + $3.69 x .25). When calculating profit for the crop, this average selling price must be used in order to be accurate. It makes no sense to move a lot of product if you are not going to make a profit. Most of us cannot afford to practice the "loss leader" philosophy that mass merchants practice. Our operations are not large enough for other products to absorb the losses.
Mixed Containers. Is there a rule that states zonal geraniums cannot be used in mixed baskets? How about ivies planted in the ground? Our current set of gardening rules have changed over the last decade. The rules have changed to the point where there are very few left to follow. If consumers are taught that shade plants wonÕt perform well in full sun and sun plants won't survive in dense shade, and if they can be taught to water and fertilize properly -- then they are free to mix and match whatever they would like to see in their gardens. Not too long ago it was considered improper to plant annuals in the perennial garden or vise versa. Demarcation lines are a lot grayer today, allowing consumers much more latitude in their garden designs than they have been used to. Make sure your marketing efforts mesh with these new trends. If consumers decide to plant a few geraniums in their perennial garden, offer a larger size that will not look lost for a month after transplant. If you are offering huge baskets of ivy geraniums, make sure you also have 4-inch pots so the theme can be carried into ground beds and window boxes. A classic, traditional look that is still popular is a window box planted with zonal geraniums in the back and ivy geraniums in the front, staggered between the zonals. The flower colors don't have to match perfectly. In fact, different shades of the same color blend together as the plants intertwine during the growing season