Plant Science: Areas of interest

Conservation Science

Regional Floristics

lespedeza leptostachya (prairie bush clover)

Lespedeza leptostachya
(prairie bush clover)

Prairie bush clover (Lespedeza leptostachya), a rare prairie plant that is 3 feet tall and very slender, survives in only a few locations within its narrow range across the Upper Midwest. The Garden is working to solve the puzzle of how to return this endangered plant to prairie ecosystems — and the key may be cows.

Some of the last remaining populations of prairie bush clover in Illinois are at Nachusa Grasslands, a former agricultural area. With the Grasslands and the state Department of Natural Resources, the Garden is testing the theory that this endangered plant benefits from cattle grazing, which results in more light, nutrients and bare earth.

"Prairies are ecosystems that are accustomed to periodic disturbances, such as fires and herds of buffalo," explained Conservation Scientist Dr. Pati Vitt, who heads the project for the Garden. "The hypothesis is that Lespedeza takes advantage of these major disturbances to repopulate itself."

The five-year field study is bringing the cows back to Nachusa in a strictly controlled way. Within 90 test plots, some grazed and some not, researchers monitor the coverage and abundance of Lespedeza plants, as well as the number of new plants. After only a year, new young plants are already appearing in the grazed plots.

The work of saving prairie bush clover also takes place in the lab. Garden scientists use new tools for genetic analysis to learn how to germinate the seeds so that the plant can be reintroduced to Midwest prairies. Meanwhile, seeds are kept safe in cold storage at the Garden.

The Garden and The Morton Arboretum, as members of the national Center for Plant Conservation, have responsibility for conserving Lespedeza leptostachya. "We have a moral obligation to try and retain as much biodiversity as possible," according to Dr. Vitt. "It is in everyone's best interest because the more diverse an ecosystem is, the more resilient it is."