Autumn Grass

In autumn, we think about the spectacular colors of the changing foliage.  Ornamental grasses found in prairies, gardens and woodland edges are also showing shades of red, tan, and gold.  They are part of the foundation of native plant species that cover prairies, savannas and meadows throughout the greater Midwest, and they are an important component in restoration projects and backyard gardens.

Grasses are classified as either cool-season grasses, which green up in early spring and go dormant by early autumn, or warm-season grasses which start actively growing after the soil is warm, typically from June 1st through late autumn in northern Illinois.  Six of the most common warm-season grasses native to this area include prairie dropseed, Sporobolus heterolepis, Northern sea oats, Chasmanthium latifolium, little bluestem, Schizachyrium scoparium, switchgrass, Panicum virgatum, Indian grass, Sorghastrum nutans, and big bluestem, Andropogon gerardii. 

All of these grasses are native to Illinois and exhibit several common characteristics.  Flowers are small, with stamens and stigmas exposed to the air.  They have no nectar, but produce large amounts of smooth, light pollen that is easily carried away by any air movement.  These grasses prefer full sun, but may grow in bright shade.  They like moist conditions in well-drained soil, and are tolerant of rocky soil and drought.  All of these species spread by dropping seed and a few also send out long, densely packed, underground root systems. 

Grasses provide sustenance for many species finding their food sources dwindling at this time of year.  Grasses can be cultivated or found growing wild in areas where it is available to cattle, bison, and horses.  The foliage is also favored by a large number of insects including grasshoppers, leafhoppers, aphids, thrips, katydids and walking sticks.  Several species of skipper caterpillars can be found among meadow and woodland edge grasses.  Along with the great quantities of seeds being produced, the insects serve as a food source for grassland bird species. 

Prairie dropseed displays pink and purple flowers in late summer with a faint odor of buttered popcorn.  It is a long-lived plant but hard to propagate, which is normally accomplished by subdividing each of its tufts.  Northern sea oats is easily grown and has become a favorite of gardeners, although it can become an aggressive spreader.  It is often used in flower arrangements for the large, flat seeds and leaves.  Little bluestem is a common grass of rocky and thin soil areas.  It is widely used in both restorations and gardens for its drought resistance and its spectacular blue and red palette.  Big bluestem has earned the nickname of “turkeyfoot” due to the way the mature seed heads display at the end of tall flower stalks.  Indian grass also grows tall and straight and maintains that posture throughout winter’s cold and wet weather.  It is used as cover by Ring-necked Pheasants, Greater Prairie Chickens, Northern Bobwhites, and Field Sparrows.  Switchgrass, another species that stays upright when wet, also provides winter cover for prairie deer mouse and house mouse.  It has been evaluated as a source of alcohol for use as an alternative fuel.  More alcohol per acre is generated by switchgrass than corn, and it is a perennial, but it is bulkier than corn making shipping and storage more costly.

Native grasses are an integral part of the landscape of northern Illinois, providing food, shelter, and protection for many birds, insects, and mammals in autumn and through winter.  With airy flower stalks, tall waving leaves, and striking colors of red, bronze, and gold, grasses add visual interest into every landscape.