Lessons from a 55 m.p.h. Cloverleaf Prairie

By Scott Woodbury

I am happy to report that the I-270 and I-44 cloverleaf prairie conversion is well underway. The combined efforts made by David Schilling (Washington University), Tamie Yegge (MDC-Powder Valley), John Behrer (Shaw Arboretum), Linda Chambers (Henry Shaw Ozark Corridor Foundation), and Mark Grossenbacher (Missouri Dept. of Transportation) have been successful. Planting plans were made, native Missouri prairie seed was purchased by MoDOT, and the seed was sown on Saturday, December 11, 1999 with the tremendous support of about 45 volunteers.

The morning began at 8:00 a.m. at Powder Valley Conservation Nature Center in Kirkwood with John Behrer speaking to the group on the importance of highway prairie plantings. He explained that prairies require a single annual mowing, rather than the typical 5-6 mowings per year for tall fescue (common cool season grass used along highways). This is a significant reduction in labor. A MoDOT official said that it would take two people a full day to mow the eight acres which have been planted at I-270 and I-44. Planting this prairie will also mean a big reduction in gasoline consumption and equipment use.

Perhaps more important is that the cloverleaf is being converted to tallgrass prairie, a common plant community in St. Louis County prior to European settlement. Henry Shaw, founder of the Missouri Botanical Garden, wrote in an 1880 manuscript, “when I first visited these grounds (MBG and Tower Grove Park) in 1820, they were called ‘La Prairie de la Barriere a Denoyer’, from Louis Denoyer who formerly lived at and kept the gate of the fence (barriere) by which the commons of the old village of St. Louis were surrounded.

For a distance of nearly two miles from where Tower Grove Park is now laid out, no trees were growing, except two or three venerable cottonwoods in the low ground…the prairie was grown over with a tall natural grass Andropogon, prairie grass, and an occasional patch of the wild strawberry, of which neither a tuft of the grass or a plant of the strawberry can now be found.” Hopefully, in the summer of 2000, prairie plants will reappear at the I-270 and I-44 interchange, reversing a nearly 200 year trend of converting “wild and weedy” prairies into lushly mowed green fescue pastures and lawn.

It goes without saying that when you create a prairie diverse with native grasses and forbs (colorful-flowering plants) you will also attract a diversity of wild animals. Goldfinches will come to feed on ripe coneflower seed heads. Dragonflies will hover over the acres of open grasses to eat from the wide array of insects which will make the prairie their new home. Even hawks are known to hang around highway prairie plantings in search of soil-churning rodents. None of these creatures ever dared to eat, drink, mate, or nest in a mowed fescue lawn, but I’ve often seen them risk life and limb to live in a 55 m. p.h. cloverleaf prairie.

This year, the cloverleaf prairie will remain just a cloverleaf. It will take a few years for most of the prairie grasses and forbs to mature and flower. Similarly, it will take a few years for the city of St. Louis to mature and warm up to the idea of converting our pasture-like lawns into urban prairies. This year, however, coreopsis, black-eyed-susan, and Canada wild rye may bloom, but so may a host of weeds. With a few light mowings by MoDOT this growing season, most weed problems should be controlled and the cloverleaf prairie will be off to a good start. After 2001, the prairie should begin to flower and attract commuters and wildlife alike. It takes a lot of nurturing and patience to rebuild an 8 acre prairie. It takes far more patience to nurture and rebuild a commitment to preserving Missouri’s prairie landscape.

Our hats should come off to the people who worked long and hard on this and to the Missouri Department of Transportation for supporting a large prairie planting on such a busy highway interchange. Please contact them at 1-888- ASK-MODO(T) with your comments.