Illinois State Prairie Grass

Big Bluestem

(Andropogon gerardii)

Adopted on August 31, 1989.

The big bluestem is Illinois' newest state symbol. On August 31, 1989, the big bluestem was chosen as Illinois' official state prairie grass by 4,316 voters from more than 50 schools and colleges. Big bluestem is a perennial bunch grass that forms large clumps which expand slowly on short, scaly rhizomes. Big bluestem, the "King of Grasses" produces better quality and greater amounts of forage than any other native American prairie grass. The big bluestem is Illinois' tallest prairie grass. It normally grows to heights of around 8 feet. The pioneers said it was as tall as a man on horseback. Its roots can reach depths of 8 to 10 feet. These deep roots help the big bluestem survive in times when there is no rain (drought). Believe it or not, one plant, grown at the University of Kentucky, grew to a height of 21 feet! No wonder the big bluestem is sometimes called the "prince of the prairie."

The habit is fairly upright, and not as arching as some ornamental grasses. Look for the blue color at the base of the stems. The stems and leaves are blue-green in early summer, developing reddish tinges as they mature. The plants turn a rich copper or orange-brown in autumn and develop an overall reddish or burgundy cast after frost. In late summer, big bluestem produces terminal 3" bronze to purplish seed heads that stand above the foliage. The flowering stalk has three finger-like branches that look to some like a turkey's foot; interesting, but not very showy. The foliage stays attractive through winter, but the seed heads disintegrate. 'Roundtree' is a little smaller than the species and a little earlier blooming. 'The Blues' has more of a blue-gray foliage. 'Pawnee' is more drooping in habit.

Culture

Big bluestem is adaptable to a wide range of soils; it thrives in light, porous soils as well as heavier, less well drained soils, even clays. It tolerates acidic or alkaline soils. It does well in dry or humid climates and tolerates cool as well as hot summers. The big bluestem grows in moist soils and lowlands and is not very plentiful in uplands. Big bluestem develops a tremendous root system which saturates the top 2 feet of soil and reaches depths of 12 feet. It was the most abundant grass in the prairies that once covered most of Illinois. It is often used for grazing by livestock now. This native plant starts its growth in April and begins to flower in late summer with most growth occurring in August. Its flowering stalk grows in three finger-like branches giving it the nickname of "turkey foot" grass.

Once established, it is very drought-tolerant. However, best growth occurs with regular watering, and plants that get adequate moisture throughout the growing season can get more than 10' tall. Big bluestem can withstand short periods of waterlogged soils in summer, but not in winter.