Look for them at Chicago-area garden centers, said Jim Ault, Ph.D., who manages the program for the Chicago Botanic Garden. He’s proud of all of them, but two are special, said Ault, the Gaylord and Dorothy Donnelley Director of Ornamental Plant Research: Baptisia ‘Lunar Eclipse’, for its flowers that change from creamy white to deep violet as the plant ages, and Baptisia ‘Sunny Morning’, for its profusion of yellow flowers on dark charcoal stems.
Read more about these cultivars on the Chicagoland Grows website.
Recently I had the pleasure of speaking at a symposium on plant exploration that was held in Des Moines, Iowa. The audience was enthralled following the plant collecting exploits of such luminaries as Dan Hinkley, one of the founders of the renowned (alas, no more) Heronswood Nursery, to far-flung locales such as Vietnam, China, and Bhutan.
Much of my presentation focused on plant collecting a tad closer to home—not as exotic perhaps, but still crucial in support of my research as the Chicago Botanic Garden’s plant breeder. So let’s go seek out the elusive wild phlox.
Phlox is predominantly a North American genus (one species sneaks into Siberia) best known for its gaudily—some say garishly colored—harbinger of spring, the moss phlox (Phlox subulata), and for that summer stalwart, the garden phlox (Phlox paniculata). For an idea of the diversity of the garden phlox, you can see Richard Hawke’s latest evaluation report on Phlox paniculata cultivars. The woodland phlox (Phlox divaricata) and the meadow phlox (Phlox maculata) also have their selections and garden advocates. It’s likely that every midwestern gardener has a phlox or two in their landscape.
Most of the remaining 60-plus phlox species are relatively unknown to horticulture, yet can delight the senses with their almost infinite variation of flower color and fragrance. The underutilized species are admittedly a persnickety group to cultivate, with many of them inhabiting harsh habitats from baking desert valleys to frigid alpine rock outcrops. So phlox breeding efforts in the past have focused (and rightly so) on the more amenable-to-cultivate species mentioned above.
My breeding work at the Garden has always focused on developing new garden plants from interspecific hybridization, or crossing different species in the same genus. I’ve used this approach to develop new coneflowers (Echinacea) and false indigos (Baptisia), to name a few. In 2006, I started assembling a collection of phlox with the intent of testing my luck in creating novel hybrids between the species here as well. The botanical and horticulture literature wasn’t too encouraging on this front, with perhaps about a dozen authenticated natural and man-made interspecific hybrids known to date. But my perseverance led to two interspecific hybrid phlox, which gardeners may be able to purchase in 2015: Phlox x procumbens ‘Pink Profusion’ and Phlox ‘Violet Pinwheels’.
You may ask,“And where is the plant exploration in this story?” I’m getting there!
Most of the phlox species simply aren’t available in the horticulture trade, yet I desired them for my breeding program. So commencing in 2011, I started my own plant collecting efforts to locate, study, and collect species phlox in the wild. Weeks were spent pouring over old taxonomic literature, maps, herbarium records and the like just to find out where phlox may yet exist in the wild. I say “may,” as the earliest records I located were from the 1940s—never a good harbinger, as urban sprawl, agriculture, and the like all too often swallow up such older stands of native plants. But records from recent years gave me strong hope that some phlox species are still “out there.” Modern collections invariably include GPS coordinates in their notes. Google Earth became my friend at this time, helping to locate potential collecting sites and plan out my trips.
Finally: boots on the ground! I’ve made local trips around northern Illinois and Indiana, and trips further afield to South Dakota, Idaho, Montana, Wyoming, and Nevada. I’ve settled into a now-familiar routine. Do my research ahead of time, as above. Then go locate the plants in bloom, which translates into days of cruising bumpy, muddy, delightfully scenic and isolated dirt roads out west with one eye on the curves and drop-offs ahead and the other on the disturbed road edges, where so many phlox tend to congregate. Phlox as a rule are resentful of heavy plant competition, and so ironically, often thrive on road edges where the occasional mower or bulldozer damage clears out the competitors. It is that or scramble up steep cliffs and talus slopes, or venture out on to harsh alkaline flats, where yet again the plant competition is light, allowing phlox to thrive.
As I find populations with plants that appear promising for cultivation, I record field notes and GPS readings, then return in another month or year with collecting permits in hand to collect seed or cuttings. Slowly, I have been building collections of several phlox species, with the hope of ultimately combining through breeding their traits of varied flower shapes, color, and fragrance, plant habits, and adaptability for cold, heat, drought, moisture, high pH, and salinity. Phlox typically take two years from a rooted cutting or a germinated seed to grow into a flowering-sized plant, so the process of growing the species and then using them in breeding is taking time. But this year marked the first I saw a significant number of plants bloom that were hybrids made between garden cultivars and wild-collected plants. As is typical in plant breeding, most of the plants were “dogs” with terrible flowers or habits, or poorly adapted to our local garden conditions. These all got the heave-ho to the compost pile. But a few gems stood out. Stay tuned for future updates!
Interested in new perennials for your garden? How about ones that have proven to be exceptional—fragrant, colorful, drought tolerant, resistant to disease and pests, and hardy in the Midwest and similar climates? Just turn to our scientists, who have done the legwork for you through the Chicago Botanic Garden’s plant breeding and evaluation programs.
Breeding and selecting new perennials is a long, intense process that begins with cross-pollinating two plants, or moving pollen by hand from the flowers of one plant to the flowers of another plant with different traits. The two related plants—which ideally will produce exceptional offspring—are selected for breeding based on desirable attributes.
“In the best-case scenario, from the first cross to the final plant worthy of introduction, it takes about seven years, maybe eight to ten. I have to think long-term in generation time, from seed to first bloom to maturity,” said Jim Ault, Ph.D., plant introduction manager and Gaylord and Dorothy Donnelley Director of Ornamental Plant Research.
The most promising new plants are propagated by cuttings or tissue culture and then scrutinized by the Garden’s Plant Evaluation Program, managed by Richard Hawke. He compares the plants to cultivars and species already in the trade to ensure that the plants from the breeding program are unique and worthy of introduction. Hawke also recommends plants for use as parents in the breeding program.
“The public can see about 80 percent of the breeding program plants as we are growing them in the ground in the evaluation gardens,” Dr. Ault said. Plants with the highest marks move to licensed commercial nurseries that also conduct field and container trials and then propagate the new plants for sale to home gardeners and the horticultural trade.
In recent years, popular offerings from the breeding program have included the first orange coneflower ever released, Art’s Pride coneflower (Echinacea ‘Art’s Pride’), and Forever Pink phlox (Phlox ‘Forever Pink’). “The interest in ‘Forever Pink’ has exploded,” Ault said. “It has three weeks of peak bloom in late May to early June and then it repeat-blooms on about 10 percent of the plant all summer and fall. It’s compact and, unlike other summer-blooming phlox, has had no powdery mildew whatsoever.”
You can expect to see more noteworthy perennials in coming years. Ault is hybridizing several types, including ground-cover phlox, asters, and other genera. “Something really wonderful should bloom this spring out of the hundreds of new seedlings that we’re growing,” said Ault.
Support for the plant evaluation program is provided by the Bernice E. Lavin Evaluation Garden Endowment, the Woman’s Board Endowment for Plant Evaluation Research and Publication, and the Sally Meads Hand Foundation.
This post was adapted from an article by Nina Koziol that appeared in the spring 2014 edition of Keep Growing, the member magazine of the Chicago Botanic Garden.