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Written by Mary P., Somerset County Rutgers Master Gardener
Sorghastrum nutans, commonly called Indiangrass, yellow Indiangrass or Indian grass, is one of the dominant grasses of the tallgrass American prairie that stretches from the east coast to the Rocky Mountains, Arizona and Utah. It is a perennial bunch grass with upright form that grows in clumps 3-7’ tall and 2-4’ wide. Like many prairie grasses, it is a warm season grass with most of its growth between June and August and a bloom time in late-summer and fall. It is noted for its blue- green leaves and showy, feathery, golden to purplish-brown flowering plumes.
The stiff, round stems are smooth and have nodes that are slightly hairy. The stems grow together in compact clusters. Each leaf is a blade, with a sheath that wraps around the stem. The sheath connects the vascular system of the blade to the rest of the plant. The blades are flat, narrowed at the base and typically long and narrow, ranging from 10-24” long and 0.2- 0.4” wide. They have a prominent midvein and a slightly rough texture on both sides. The blades are blue-green in summer, turn orange-yellow in the fall and retain hints of color into the winter.
The grass stays low most of the year and gets tall while producing flowers and seed heads from August through October. The inflorescence which tops the stem is a single, dense panicle, initially erect but arching slightly as it matures. It is usually 5-12” long with many short branches. Spikelets, golden-brown and 0.2-0.3” long, are arranged in triads of one fertile spikelet and two sterile spikelets along each branch. Each fertile spikelet has one perfect flower without petals called a floret that has three large, showy, yellow stamens. The sterile spikelets with no florets aid in wind dispersal of pollen. The coppery-colored seeds are 0.2-0.3” long with a prominent bent awn (hairy appendage) 0.4-0.6” long that helps the seed adhere to the ground. The panicles darken to bronze/chestnut brown as they mature, later fading to grey.
Indian grass thrives in full sun with moist, well drained soils of all types. It tolerates poor, dry, infertile soil and is very drought and deer resistant. It has no serious insect or pest problems, provides nutritious forage for birds, wildlife and livestock, is effective on slopes for erosion control and can grow in shallow rocky soil. It has been recommended as an excellent native alternative to the invasive Miscanthus sinensis, also known as Chinese silvergrass.
Two cultivars that are noted for the blue color of their leaves are ‘Indian Steel’ and ‘Bluebird’. ‘Indian Steel’ is noted for its striking, steel-blue colored foliage, which is significantly more pronounced than the typical leaves of the species. It is also often noted for its superior ornamental value and ability to retain its golden fall color longer into winter compared to the standard species. ‘Bluebird’ is a shorter bluish-leaved cultivar that usually grows 3-5’.
Resources:
NC State Extension Sorghastrum nutans
Ladybird Johnson Wildflower Center: Sorghastrum nutans
Native Plant Trust: Sorghastrum nutans — Indian grass