Indian Grass - A Tough Native Plant
Mary Meyer, Professor & Extension Horticulturist, University of Minnesota
Indian grass, Sorghastrum nutans, is an underused native grass. Found throughout the U.S. (except CA, NV, ID, WA and OR), Indian grass grows on a wide range of soils, but prefers loamy rich, wet to mesic sites. Occasionally it is found on upland areas with heavy clay soils, as long as there is sufficient moisture. Plants.gov database describes site preferences as “deep, well-drained floodplain soils and in well-drained upland sandy loam soils; tolerant of poor and well-drained soils, acid to alkaline conditions, and textures from sand to clay.” Indian grass has striking blue green summer foliage grows quickly from June through August. The showy golden bronze flowers are often bright yellow with prominent anthers, which accounts for the another common name: yellow Indian grass. Because this was one of the main grasses in the tall grass prairie, we can find it along roadsides and in prairie remnants throughout Minnesota. Uses for Indian grass include seeding large or small areas for restoration purposes, or using individual plants in a smaller garden or landscape setting.
The Minnesota Department of Transportation uses Indian grass in native mixes for wetter areas, along with sedges in wetland restoration, and general mixes for native roadsides. Indian grass grows well on disturbed sites, produces abundant seed, and is good for erosion control and difficult slopes. Restoration companies know the value of Indian grass in native mixes. The University of Minnesota was involved with a 1988 release of the Indian grass variety ‘Tomahawk’, along with North and South Dakota Experiment Stations and the NRCS Plant Materials Center in Bismarck, ND. Seed for this selection was collected in early 1960’s from Dickey and Brown counties, in southeastern ND; and Marshall county, north eastern SD. ‘Tomahawk’ is the only variety of Indian grass that is selected from northern seed; all other NRCS selections originate from more southern states, such as Nebraska, Oklahoma, Texas, and Kansas. Indian grass from theses states matures later and is more subject to winter injury. ‘Tomahawk’ is a good selection for prairie restoration, pastureland, livestock, rangeland, habitat cover, and roadside use in Minnesota, and North and South Dakota.
Garden and Landscape Plantings
In gardens and more urban plantings Indian grass has a place in many settings. Its tolerance of heavy clay soils and endurance (once established) to full sun and hot summers makes it a sustainable grass for difficult sites. With its taller stature, Indian grass makes a good border or screen hiding a fence or marking a boundary. Garden selections, ‘Indian Steel’ and ‘Sioux Blue’ are large plants that are good substitutes for miscanthus. A gardener told me recently she removed her Indian grass because it was too floppy and messy, which may happen in areas of shade or high nutrient soils. ‘Sioux Blue’ was selected by Rick Darke from the seed propagated NRCS variety Osage, which originated from Kansas and Oklahoma. ‘Sioux Blue’ has powdery blue foliage in summer and numerous cinnamon colored flowers in early fall and flowers a few weeks later than Indian grass from Minnesota or the Dakotas. ‘Indian Steel’ is a seed-propagated cultivar introduced in 1995 by Jelitto Perennial Seeds. Blue foliage and upright vase-shape are characteristic of ‘Indian Steel’. Origin of this cultivar is unknown. Both ‘Sioux Blue’ and ‘Indian Steel’ are large plants, usually 6’-7’ in height. ‘Bantam’ and ‘Red Spike’ were announced as named cultivars under evaluation by Iowa State in 2010, but have not been available in the trade.
From 2005-2010, I evaluated 24 different Indian grass selections from South Dakota. Over 7 seasons, I looked for desirable landscape traits and selected 6 plants that we are evaluating further at the Minnesota Landscape Arboretum. These are diverse plants, and all flower earlier than ‘Sioux Blue’ or ‘Indian Steel’.
Indian grass supports wildlife, with its dense cover, and I find birds love to forage on the seedheads at the Arboretum. Bees sometimes feed on the pollen; skipper butterfly larvae feed on the foliage; whitetail deer brose foliage; songbirds and bobwhite quail, mourning doves feed on seeds; and prairie chickens use the plants for feed and cover.
The WCROC participates in Indian grass research. In June of 2015, Steve Poppe, along with Mary Meyer, Professor and Extension Horticulturist, U of MN, planted two promising selections of Indian grass in our horticulture research plots. The objective was to evaluate these two selections for vigor, flowering time, floral impact, no lodging and good winter interest.
These two selections of Sorghastrum nutans came from South Dakota State University. They were previously evaluated at the MN Landscape Arboretum, and appeared to have best forms for landscape use. They also flower in late August, instead of late September, when ‘Sioux Blue and ‘Indian Steel’ flower.