UT Extension News: “Native Warm Season Grasses”

June 23, 2020

by Chris Hicks, County Director – UT Extension Smith County

Native warm-season grasses (NWSG) are grasses historically native to an area that grow during the warm months of the year and are dormant during autumn and winter. NWSG can provide quality forage during the summer slump, supply wildlife habitat, and even have the potential to fuel our vehicles.

While there are many warm-season grasses native to this area, seven are commonly promoted for forage and wildlife cover. These include big bluestem, little bluestem, broomsedge bluestem, indiangrass, switchgrass, sideoats grama and eastern gamagrass. These grasses differ widely in their value for forages and wildlife cover.

Big bluestem is a warm-season perennial that spreads by short rhizomes, creating clumps. Stems may reach 8–9 feet, depending on variety and site conditions. Growth begins in April; however, the majority of growth occurs after June 1. Big bluestem grows on a wide variety of soils, even on sites with a pH as low as 4.0. Big bluestem is extremely drought-tolerant, with root systems that may grow 12 feet deep.

Little bluestem is a warm-season perennial bunchgrass that grows 2–4 feet in height. Primary growth occurs from mid spring through summer, reaching maximum height in July. Mature plants are reddish-brown and can grow on a wide variety of soils.

Broomsedge is a warm-season perennial bunchgrass that grows 2–4 feet in height. Growth begins in the spring when daytime temperatures reach 60–65 degrees F. Although similar in appearance to little bluestem, broomsedge is lighter in color and has seedheads enclosed in a large straw-colored spathe which little bluestem doesn’t have. Broomsedge offers excellent nesting for wildlife, but is a very poor forage.

Indiangrass is a warm-season perennial that spreads by seed and short rhizomes. This heavy seed producer normally occurs in bunches, much like big bluestem. Growth begins in April and can reach 3–7 feet in height, depending on site. A unique characteristic that differentiates indiangrass from other NWSG is a prominent, notched ligule. Its deep root system makes indiangrass very drought tolerant.

Switchgrass is an early-maturing warm season grass that typically reaches a height of 3-6 feet. It is adapted to a wide array of soil types and site conditions and its extensive root system makes switchgrass extremely drought tolerant. Switchgrass generally produces 4-5 tons of forage per acre.

Eastern Gamagrass is a warm season perennial that starts growth in early spring, reaches a height of 5-9 feet, and usually remains green until the first frost. It produces excellent forage for grazing and haying with yields similar to switchgrass.

Sideoats Grama is a warm-season perennial that spreads by short rhizomes. It grows to a height of 1-3 feet with seedstalks appearing in June and July. Sideoats grama grows well on well-drained uplands and shallow ridges, but is not well-adapted to lowlands.