785 Sorghastrum nutansCommon Names: indiangrass, yellow indiangrass Family: Poaceae (grass Family)
Indiangrass is a tall bunchgrass that typically grows in clumps about 1 ft (0.3 m) in diameter. The numerous short scaly rhizomes may mat together to form a dense sod with roots extending 6 ft (15.2 m) into the earth. In the spring, a cluster of pale green to dusty-bluish leaves emerges from the root mass to form a robust clump of gracefully upright foliage 1-2 ft (0.3-0.6 m) high. The 0.5 in (1.3 cm) wide leaves are narrower at the base, 10-24 in (25.4-61 cm) long, stiff, smooth, and flat. They emerge from sheaths shorter than the internodes at a 45 degree angle from the stem. Under ideal conditions, this grass may get 5-7 in (12.7-17.8 cm) high by the end of the season, when it takes on its rusty gold fall color. In late summer, silky golden flowering plumes appear above the foliage. These compact panicles are 4-12 in (10.2-30.5 cm) long and 1-3 in (2.5-7.6 cm) in diameter. The plumes are a bronzy color with contrasting hairy grayish branchlets, white fringed spikelets, and showy bright yellow anthers that create a sparkling gold-and-silver effect. The roundish tawny beige-tan seeds have tail-like 0.5 in (1.3 cm) long wiry awns that are bent and twisted in such a way as to make the seedhead look a bit frizzled.
This is a warm season grass that begins growth in midspring after the soil has begun to warm up. The timing of flowering and seed production seems to be genetically influenced; plants from southeastern sources flower earlier than those derived from upper Midwest stock. Indiangrass generally matures between September and November in the prairie states, whereas blooms appear and seedheads form in August-September in the Southeast. Numerous cultivars have been selected for their regional adaptations, forage potential, revegetation usefulness, and wildlife value.
Indiangrass, Sorghastrum nutans, is native to North America east of the Rocky Mountains from Saskatchewan to Quebec and south into northern Mexico. This species originated in prairie and savanna habitats and grows in a wide variety of dry to mesic woods and meadows. Indiangrass readily invades disturbed sites with bare soil and now may be found along roadsides, in old abandoned farm fields, and on reclaimed lands. Common associates include its fellow tallgrass prairie co-dominants, big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), and switchgrass (Panicum virgatum). Indiangrass is a relatively minor component in northern prairies, but becomes increasingly more dominant to the south. Range managers consider indiangrass an indicator of healthy prairie that has not been overgrazed. Decay of this species' fibrous roots is an important contribution to prairie soil formation.
CultureIndiangrass grows on a wide variety of soils, including some that are sandy or gravely, but it is most luxuriant on rich, moist, fine textured bottomland types like deep silty loams. It will tolerate heavy clays, limerock, mild salinity, and soil pH as acidic as 4.5. Indiangrass delights in fertilizer and irrigation. It should not be mowed or grazed at all the first year. Grazing must be managed carefully on pastures incorporating this species because Indiangrass is a "decreaser" that declines in response to livestock use. It is highly intolerant of repeated close grazing and should never be cut shorter than 4-6 in (10.2-15.2 cm). Indiangrass evolved with prairie fires and does best when burned frequently. Burning will destroy seeds, but the underground rhizomes will quickly send up new shoots and the grass will rapidly regrow with increased density, vigor, and flowering. Burning every 3-5 years is generally recommended for prairie management, but indiangrass will grow even more enthusiastically if burned annually. A late spring headfire is ideal. Light: This is a grass that will grow in part shade, but does best in full sun. Moisture: Indiangrass grows best in moist soil. It will tolerate water tables that sometimes rise within a foot of the surface, occasional sogginess, and even accept brief flooding, but it will not tolerate prolonged soil saturation. Hardiness: USDA Zones 3 - 9. Propagation: Indiangrass sheds its seeds soon after they mature, but they require a season's dormancy at winter temperatures before they will germinate. Fresh seed may be sown in the fall and expected to sprout when the soil warms up in the spring, or firmly planted 0.5 in (1.3 cm) deep in early spring. A seeding rate of 4-10 lbs. of live seed per acre is recommended. If the seeds are to be mechanically planted, they should be "debearded" to remove their tail-like awns first. The seedlings are tougher than those of most grasses and can be transplanted while quite young and expected to survive early dry spells better than might be anticipated. Propagation by division is also possible, but it is likely to be challenging due to the tough matted rhizomes. Transplants may be set out in either spring or fall.
Indiangrass is recommended for use as an accent in landscapes where North American native species are preferred over exotic ornamental grasses such as Miscanthus, fountaingrass or pampas grass. Indiangrass is widely used in large scale roadside plantings and revegetation, prairie restoration, rangeland improvement, and erosion control projects since it grows well on disturbed sites and produces abundant seeds that are readily harvested and easily sown by hand or machine. When it is in active growth, indiangrass makes a nutritious pasture grass rich in protein and vitamin A. The forage value of Indiangrass decreases rapidly later in the season however, and it is regarded as a low quality supplemental pasturage in the fall and winter. Indiangrass does not make very palatable hay and decreases in density if cut at the hay stage, so this use is not recommended.
Indiangrass is a wonderful drought resistant meadow grass that is a legitimate and desirable native component in most eastern North American grasslands. It may be grown intermixed with native cool season grasses as well as with comparably assertive wildflowers and warm season grasses. Indiangrass is an aggressive competitor. Don't plant it amongst fragile wildflowers! Indiangrass attracts wildlife too. Bees come to the blossoms, songbirds and small mammals eat the seeds, and deer browse the foliage. It also provides excellent nesting sites and cover for pheasants, quail, mourning doves, and prairie chickens.
Linda Conway Duever 8/28/00; updated 11/26/03, 4/24/11