August Home-Garden

National Gardening Association Geranium Outlook

By Shelly Stiles

It was in 1904 at a win against Princeton when "the fiercest beast that ever lived" first led a Penn State team out to the diamond. The university's sports fans still raise a roar when urged on by their fear-inspiring mascot, the Nittany (mountain) Lion. (Mount Nittany is a State College, Pennsylvania, landmark.) The same kind of excitement was generated among Pelargonium breeders in 1962, when the Penn State Department of Horticulture team took the field. Their record breaker: "Nittany Lion Red," the first commercially successful seed-propagated zonal geranium.

Before Nittany Lion's release, garden geraniums, all botanically the hybrid Pelargonium x borlorum, were propagated vegetatively by cuttings. Cutting-propagated geraniums still capture most of the geranium market. But now, home gardeners can enjoy the challenge of growing their own brilliantly colored bedding geraniums from seed. And, at about $2.50 per packet of 10 seeds rather than $2.79 per potted cutting, geraniums can fill planting beds without breaking the budget. Homegrowns offer excellent garden performance as well, even where conditions are too sunny or hot for most cutting-propagated varieties. Many growers find that seed geraniums flower much more abundantly and for longer periods of time - often from last to first frost - than do cutting geraniums.

It wasn't affordability or good garden performance, but a crisis in the commercial geranium industry that led Penn State researchers to the development of a seed- propagated geranium. Dr. Richard Craig, now professor of plant breeding at Penn State, remembers well the day more than 30 years ago that put him on the trail of the Nittany Lion. "I was in a plant pathology class," he recalls, "a junior on my way to a degree in plant genetics. My professor remarked, as an aside, that if we could grow them from seed, we could have diseasefree geraniums. (California geranium crops had just been devastated by bacterial blight, Xanthomonas campestris pelargonii.) I heard that, and nothing else. My mind went 'pfghht.' I was already planning my senior project."

Craig encountered an early and persistent problem with propagating Pelargonium x bortorum from seed: poor germination, usually no higher than 40% or 50%, and then only after several months. Avery hard, water-resistant seed coat seemed to be the culprit. The research team tried "weathering" the seed with hot and cold water, abrading it with sandpaper and rinsing it with acid baths. They eventually found that if the seed coat was nicked with a razor blade, they could get almost 100% germination in just a couple of weeks. As Craig says, "Once you can germinate, you can breed." And breed they did. Several generations of geraniums later, trial geranium G54 made its debut. Later to become Nittany Lion Red, this pioneer was a somewhat rangy, lateblooming plant that, despite a special commendation from the All-America Selections organization in 1962, few of us would want in our gardens or window boxes today. But commercial breeders were encouraged by Penn State's success, and envisioning a rosy future for seed geraniums, they set out to prove that seed-propagated varieties could offer more.

Geraniums Grow Up

Like the Penn State pioneer, other introductions of the '60s were tall and slow to flower. The New Era series, the first F, hybrid commercial seedpropagated geranium, was released by Harris Seeds in 1966. (All of today's named seed-propagated varieties are F1 hybrids.) Unlike Nittany Lion, New Era came in lots of colors - white, coral, red, bright red and salmon. Carefree, a triple All-America Selections winner, was introduced two years later by PanAmerican Seed Company. It too offered several color choices, including red with a white eye and a red picotee. But though Carefree was smaller than Nittany Lion at bud break, most commercial growers felt it was still too large, especially for container culture. And they wanted plants that didn't take quite so long to bloom.

In the '70s, seed geranium breeders gave the growers what they wanted. The Sprinter series, a joint introduction from Sluice and Groot and Goldsmith Seeds Inc., reduced pre- bloom time to about 16 weeks. orbit, also from Goldsmith, and Ringo, another Sluice and Groot introduction, bloomed in as few as 15 weeks from sowing on plants about a foot tall, and are both still commercially popular series. Recent introductions have reduced the prebloom period to as few as 12 weeks, about the same as taller varieties of snapdragons. Bandit, a 1989 introduction by Denholm Seeds, is just such a "preemie," blooming in 12 to 14 weeks on compact plants.

Breeder Blair Winner at Denholm explains that three factors were involved in the quest for Bandit's shorter pre-bloom period. All geranium varieties, he says, have a genetically determined juvenile phase, during which nothing the grower can do will initiate flower bud formation. Once the plant is past the juvenile phase, however, bud set can be initiated by high light levels. And its floral show can be promoted by warm growing temperatures. Bandit, like other early-blooming varieties, combines a shorter juvenile phase with lower light requirements for bud set and lower temperature requirements for blossoming. A wider range of flower colors is another goal of today's seed geranium breeders.

Though brilliant scarlets and orange-reds are still highly popular, pastels now capture a larger part of the entire geranium market. Chuck Heidgen, owner of Shady Hill Gardens, geranium breeders and suppliers in Batavia, Illinois, says that about 60% of the cutting and seed geraniums he sells are in pastel shades. Not all new colors are "tender," though. The first true orange geranium on the market, Orange Appeal, will be introduced by Goldsmith to commercial growers this month.

Seed geranium breeders are also trying to develop in their varieties the kind of flower color patterns found in cutting-propagated cultivars. A soon-to-be-announced 1991 All-America Selections winner bred by PanAmerican Seed Company is a case in point. (Its identity is a secret until September, when the plant will be released to the home gardening trade.) The cultivar's pink petals are brushed with deep rose freckles near their base, and the "throat" of the flower is white.

Another characteristic sought by geranium breeders in the 1990s is brighter and more varied leaf zonation. Though cutting-propagated geraniums are better known for their "fancy leaves," concentric dark and light green, or red and green leaf patterns are found in Bandit as well as in the older Orbit, Ringo, E Pinto series. It's botanically impossible to get zonation on white or partially white geraniums, however. These flowers, and any flower colors created by a cross with a white variety, are genetically linked to solid green leaves.

Hit Singles

Today's breeders are also selecting for a larger number of flowers per plant. Goldsmith's Multibloom, released in 1989 but available to the home gardener for the first time this year, excels in its "free flowering" characteristic. Each six- to eight-inch plant may carry as many as 15 flowers at any time. The series features eight different colors from red to white to lavender. Because the plants are rather small, breeder Niles Riese at Goldsmith suggests using them in mass plantings rather than in containers. Jan Umsted, senior product manager for seeds at Ball Seed Company, recommends spacing them tightly in the bed. Multibloom will flower early and keep going until the first killing frost.

Seed geranium breeders use the phrase "free flowering" to describe not only a large number of flowers carried on each plant, but a rapid replacement - within hours, in some cases - of flowers lost to wind or rain. This loss of flowers, called "shattering," or more generously, "self- cleaning," is a special problem of seed-propagated geraniums.

Geranium specialists aren't sure why, but single flowers - those with five petals, as are found in all natu- rally occurring members of the geranium family - tend to shatter, while semi-double and double-flowers are long lasting. The extra petals in semi-double and double flowers are derived from the male and female reproductive organs. According to Richard Craig, such deformed flowers are highly sterile: they don't produce much Pollen, and even when painstakingly hand pollinated, they often don't set viable seed.

Though there are hundreds of named variety semi-double and double cutting-propagated geraniums, poor seed set can make breeding new ones a slow process. But seed propagation of cutting-propagated geraniums is important only during the variety development stage. Once bred and selected, these doubleflowered varieties are propagated vegetatively

For seed geranium breeders, however, poor seed set is a problem not only in the development phase, but also in the production stage. The expense involved in securing a seed harvest, usually a small one, makes double-flowered seed- propagated varieties infeasible for most commercial breeders. And for now, and into the future, all seed geraniums are singles. So the rapid re-flowering characteristic of many of the new cultivars is likely to remain the breeder's best response to shattering for some time.

Poor seed set hampers progress toward another goal of geranium breeding in the 1990s: tetraploid cultivars. The tetraploid geranium, a spontaneous mutation first noted in the late 19th century, has twice the number of chromosomes that other geraniums have. (This "4n" - for four sets of chromosomes - line was bred separately from the normal "2n" or diploid line, and is in the parentage of many of today's cutting geraniums.) The reason for this is not understood, but twice the number of chromosomes means better garden performance. (Tetraploid vigor is commercially important in other breeding programs. "4n" cultivars are increasingly common in the daylily world, for example.)

Jan Umsted at Ball Seed says that tetraploid geraniums, such as PaAmerican's upcoming introduction, are sturdier, stockier, may have greater disease resistance and carry larger flowers than diploid geraniums. But tetraploid fertility is low - no more than 20% of that of the chromosomally normal geraniums, according to Richard Craig. When tetraploids do set seed, their greater number of chromosomes makes for a more genetically varied and unpredictable set of offspring, anathema in a business where uniformity is all-important.

Though seed geranium breeders have had some success selecting for better germinating varieties, Richard Craig's problems with a hard seed coat have not gone away, 30 years later. But home gardeners who purchase geranium seed won't have to nick each one with a razor blade. The seed producer will have already done that, or something like that. Blair Winner says that at Denholm Seeds, as at other companies, all the geranium seed they sell is prescarified. just how they do this is a trade secret. (He acknowledges that most breeders use an acid bath or an abrasive, but won't give more details.)

Growing Your Own

Even though scarified, purchased geranium seed still has pretty particular germination requirements. Chuck Heidgen suggests sowing the seed some 16 to 18 weeks before the last frost date (sometime in January in the Chicago area), in a germination medium kept at 75 degrees F. Winner recommends a somewhat cooler sowing medium temperature of 72 degrees to 74 degrees. Under such ideal conditions, he says, seed should germinate in seven to 10 days. Gardeners who can't offer the ideal shouldn't give up on growing geraniums from seed, though. Winner says that seed will sprout even in cooler germination media, but erratically, and over a few weeks' time.

Though light isn't required for germination, once sprouted the tiny seedlings are desperate for it, and won't branch well and at short intervals without it. Heidgen recommends growing young plants under fluorescent lamps hung 12 to 18 inches above the seedlings, and lit 16 hours a day. High light levels not only make for thrifty plants, but also ensure early bud set. Winner cautions that young geranium seedlings so need light that windowsill gardeners shouldn't expect to be able to grow a plant as compact and sturdy as those sold in nurseries and garden centers. And even the best home-greenhousegrown specimens won't be as stocky as commercially produced plants.

Though the tendency to reach for the sky that was, common in the early seed geraniums has been bred out of them, commercial growers still use a growth retardant during the juvenile stage to ensure short internodes. Growth retardants also make it possible for commercial growers to crowd plants tightly on the greenhouse bench. Chuck Heidgen vetoes growth retardants for the home gardener, comparing them to prescription drugs. "They're too easily misused," he says, "and because they aren't sold in home gardener packaging, they're awfully expensive."

After germination, once the first set of true leaves appear, the seedlings should be transplanted to 2 1/4-inch pots. Heidgen suggests feeding established transplants every second or third watering with a water-soluble fertilizer mixed at half the recommended rate - a 20-20-20 preparation or fish emulsion are good. As the seedlings increase in size, transplant them again to a four-inch or larger pot.

Commercial growers use different temperature regimens, some of them with nights as cool as 50 degrees F, to bring their crops to salable size. Home gardeners can grow their seedlings al- most as cool, at an average temperature of around 60 degrees F, though slightly warmer temperatures will shorten the time to flowering. Heidgen encourages home gardeners to get their geranium seedlings outdoors in bright light as soon as they can. A heated cold frame, he says, is ideal for the hardening-off period. For those who can't control the growing environment as completely as they'd like, Heidgen offers some encouragement. "Warmth and light are important, but I think the most effective growth regulator is water, judiciously applied," he says. "Pelargoniums are native to South Africa, where they grow in dry, well-drained soils. A plant grown on the dry side in bright, cool conditions will be more compact than one grown in wet soil under the same conditions."

Geraniums will not withstand frosts, and Heidgen recommends paying close attention to weather forecasts during their hardening-off period. When to put them in their permanent locations? "The day after the last frost, of course!" he says.

Provided by NGA.
Reprinted with permission, HouseNet, Inc.

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