Forest Preserve District of Cook County, Illinois
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Wildflower Restoration in the Forest Preserves
Nature Bulletin No. 755   May 9, 1964
Forest Preserve District of Cook County 
Seymour Simon, President
David H. Thompson, Senior Naturalist

Wildflowers are among the main attractions of our forest preserves. From the time the first blooms appear in spring until the last ones are killed by frost in autumn, thousands of visitors come to enjoy them. The greatest abundance of native flowers and the widest variety of kinds are invariably found in those areas which had been disturbed least by man before they were set aside as forest preserves.

Too often, other parts of our holdings have a previous history of plowing, draining, grazing, logging and burning. Wildflowers were sharply reduced or almost completely wiped out. In the woodlands, which ordinarily yield the finest displays of early spring flowers, some were cleared of trees and planted in farm crops. In others only the best trees were cut, the rich leaf mold and ground cover burned to promote the growth of grass, then pastured and trampled by livestock.

Today, after as much as forty years of protection as forest preserves, many parts of these woodlands have regained their natural leaf mulch and understory of shrubs and small trees. Conditions again seemed suitable for many kinds of wildflowers but they have been slow in spreading naturally into these restored areas.

Beginning about ten years ago, one of our naturalists who is a skilled gardener began to transplant several kinds of conspicuous and colorful flowers from areas where they were plentiful into promising spots that lacked them -- bluebells, white trillium, Dutchman's breeches, bloodroot, shooting star and wild columbine. As this was continued on a small scale for several years it was found that a surprising number of these plants survived and multiplied in the new locations.

Then he began to grow his own plants in garden plots from seed, or from bulbs, root cuttings and other underground parts. Almost every species was a separate problem which must be solved by ingenuity and experimentation. Very little practical information could be found in books. Seeds of the different kinds must be gathered at different seasons, stored in special ways, or perhaps refrigerated to break their dormancy before planting. Each has its own requirements of soil, moisture, drainage, sunlight or shade, which is best learned by studying conditions where the flower grows in the wild.

Two years ago a five-acre wildflower nursery was started with the purpose of propagating the more showy and interesting kinds for restocking the preserves. At present about thirty species are being grown, with more to be added as the project develops. These are about equally divided between spring woodland bloomers and the sun-lovers of prairies and open country.

Most of the woodland species being grown have large underground stores of plant food -- roots, bulbs, tubers or corms -- which allow them to push up rapidly in spring, bloom, set seed and recharge their stores before the leafing trees cut off the sunlight. Others such as fire pink, blue phlox and wild columbine are grown from seed. At every opportunity these -- as well as other kinds -- are rescued from areas where highways and other construction projects threaten them with destruction.

With few exceptions the prairie species in the nursery are grown from seed. These give bright bands or splashes of color in summer -- cardinal flower, great blue lobelia, coreopsis, purple coneflower, blazing star and butterfly milkweed, to name a few. An exception is the picturesque Turk's cap lily which is propagated from scales on the root.

Of the former prairies in the Chicago region only a few fragments have survived. As part of this wildflower project it is planned to restore about a dozen areas of one or two acres each where people can get a glimpse of some of the flowers that made Illinois the "Prairie State."

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