For half a century, Robert Griesbach, PhD'55, has cultivated his garden, working to build a better daylily. Griesbach's latest is a deep purple beauty - named for his U of C mentor.

On his five-acre farm, nestled between crops of corn and soybeans in Delavan, Wisconsin, Robert Griesbach, PhD'55, spends his summers tending to more than 10,000 daylily plants that form a tightly packed field awash in hues ranging from pink and red to yellow and near white. Yet every year or so, he disrupts this tranquil scene by digging up and transplanting a few choice blooms, before applying herbicide to kill off the remaining thousands. The next year, he starts the process over by replanting the field with seeds produced from hand pollination.

Robert Griesbach, PhD'55

The ritual is part of Griesbach's six-decade pursuit of new daylily varieties. To date, he has introduced some 60 new daylily plants through a number of nurseries, including Klehm's Song Sparrow Perennial Farm in Avalon, Wisconsin, and Wayside Gardens in South Carolina. A professor of biological sciences at DePaul University for 34 years, Griesbach developed a new method for doubling the chromosomes in daylilies-with four sets of chromosomes, tetraploids offer more color possibilities. His latest creation is a deep, velvety purple daylily to be named in memory of his mentor at the University of Chicago, botanist Paul Voth, SM'30, PhD'33.

Griesbach's father, a church organist and choir director, grew irises and other flowers on their city lot in Menasha, Wisconsin. Though always interested in plants from working with his father, Griesbach's interest in daylilies blossomed upon coming to the University and doing graduate work under Voth. A 1940 Quantrell winner who himself had studied under U of C botanist and daylily breeder Ezra Kraus, PhD'17, Voth suggested that Griesbach study daylily dormancy and germination to arrive at a more exact reading of the effect of cold temperatures on deciduous daylilies.

What prompted breeder Robert Griesbach's interest in daylilies was, he explains, the realization that "daylilies were going to become the most important garden perennial."

Voth was a dedicated mentor, hand-pollinating daylilies to produce the seeds Griesbach used in his experiments. Unlike evergreen daylilies, which keep their foliage year round and grow well in the southern United States, deciduous daylilies lose their foliage in the fall and are more common in the northern United States. Griesbach found that deciduous daylily seeds must be in the ground at a near-freezing temperature for six to eight weeks before they start to develop; they can still germinate after being exposed to slightly warmer conditions, but must remain at those conditions for a longer period of time. His findings helped give evidence to what had previously only been noted anecdotically.

After completing his graduate work in botany at Chicago, Griesbach returned to teach at DePaul-where he had earned his bachelor's and master's degrees-in its biological-sciences department, eventually chairing the department for 14 years. At DePaul, he was able to blend his scientific work in cytology and the genetics of polyploidy (plants with more than the normal number of chromosomes) with what quickly became a lifetime interest in breeding daylilies. "My research and my hobby were all combined," he says. "I continued school, so to speak, on Saturdays and Sundays."

What prompted his interest in breeding daylilies, he explains, was the realization that "daylilies were going to become the most important garden perennial." It's a strong statement from a generally mild-mannered professor, but he saw plenty of evidence to back his argument: Daylilies can flourish in a variety of soils, temperatures, and light intensities. They also have a long growing season, from late spring to autumn; every day brings a new group of blossoms; and, in the northern United States, they can be grown without being mulched. But perhaps their greatest feature is being extremely resistant to fungal and viral diseases. Today, Griesbach's confidence has proven well-placed: The American Hemerocallis Society boasts over 10,000 members, publishes the quarterly Daylily Journal, and hosts regional and national conventions and growers' competitions.

Griesbach began his breeding experiments by working to develop tetraploid daylilies, which have four sets of chromosomes instead of the two sets common in many plants. In increasing the number of chromosomes, his goal was to deepen the daylily gene pool and thus expand the possible variations of color and other physical attributes. Taking the seedlings left over from his dissertation experiments, he treated them with the chemical colchicine, which caused their cells to begin to divide-creating a duplicate copy of the chromosomes-without completing the cell-division process. This plant was left with cells with the genetic material for two individual cells.

Two years after his tetraploid first bloomed in 1959, Griesbach formally introduced the new flower. Crestwood Evening, which he had collaborated on with breeder Orville Fay, made its debut at the 1961 National Daylily Convention in Chicago.

The new tetraploids were noticeably different from their diploid ancestors. With twice as many chromosomes, cell nuclei were larger. With larger cells, the tetraploids had larger flowers, leaves, and roots. An increased root system meant that the tetraploids could absorb more water and nutrients, and thus grew more vigorously. Doubling the chromosome number also meant that the tetraploids' color could be more intense, because the new plants could have as many as four doses of a given pigment, while diploids could only range from zero to two doses.

Not all of the results were desirable. The new plants were stiff and sometimes brittle. And, because they were temperature sensitive, the first generation of tetraploids was not very fertile: if the temperature exceeded 80° F, pollination would most likely not take. But Griesbach eventually found that such undesirable qualities could be bred out of the daylilies in second, third, and fourth generations.

Asked to name some of his favorite creations, Griesbach thinks over his answer carefully. Ruby Throat, Towee, Baltimore Oriole, Painted Trillium, and Blazing Sun win the honors. "One of my interests was to work on certain colors that, at the tetraploid level, were not very well established, and red was one of them," he explains. Ruby Throat and Towee, for example, offered a clearer, less muddy red than previously available. Although he has worked on many colors to improve their clarity (how pure a color is), saturation, and intensity, Griesbach admits that all his favorites fall in the reds and purples.

Retiring in 1989, Griesbach moved to Wisconsin with his wife, Mary Lou, in 1991. The relocation took two years because he had to transfer two crops of flowers-daylilies and lilies. In the end, Griesbach transplanted several thousand plants from his home in Park Ridge, Illinois, to his new farm in Delavan, Wisconsin. His summer 2000 crop now includes 3,000 daylilies blooming for the first time this year and representing 150 different parents. Of these 3,000, only three to four will be improved enough for possible naming and introduction; those improved but not significantly improved enough for introduction will be used for crosses to produce seeds. The hope is that with each generation, the resulting plants will become more and more improved in terms of the particular trait for which Griesbach is breeding them.

Among the flowers growing in his field are several plants of the Dr. Paul Voth daylily, to be registered with the American Hemerocallis Society this summer. Griesbach plans to introduce the flower to the public in 2001, which will be sold through Klehm's. Griesbach chose to name this deep, velvety purple daylily after Voth both because, as daylily hues go, it's one of the more "manly" hues, and because it's in Griesbach's own favorite color range. "Dr. Voth was the one who really got me interested and involved with daylilies in the first place," says Griesbach. "I learned so much from him about daylilies, I just feel that it's very appropriate to honor him in this way."