Big bluestem is one of the native, warm-season bunchgrasses noted for their rapid growth during mid-to-late summer when high temperatures retard the growth of cool-season grasses. The primary use of big bluestem is as a livestock forage seeded in pure stands or in mixtures. It also produces excellent hay and cover for soil erosion control. It is not rated as highly as switch grass or Indian grass for wildlife cover because snow on mature big bluestem can cause severe lodging and loss of winter protective cover.

Big bluestem produces a deep, extensive, fibrous root system and short rhizomes. It begins growth somewhat later than switch grass, usually in late April or early May. Big bluestem's growth increases rapidly with higher temperatures. It produces about 70 percent of its annual growth after June 15. Its average date of seed maturity is September 9. If undisturbed, it attains a height of four to six feet, and establishes a very deep root system. Big bluestem plants can be distinguished from other warm-season grasses, even when plants are young, by the long, white hairs on the stem and upper leaf near the base of the leaf. The stem is round and has a reddish tint at its base. The seed head normally has three, finger-like branches shaped like a turkey's foot.

Big bluestem is winter hardy, and will grow in all areas of Missouri. It is suited to all soils when planted, except those saturated for an extended period. Deep, well-drained soils are preferred. One variety of big bluestem recommended for use in Missouri is 'Roundtree.' It was released for public use by the Soil Conservation Service's Elsberry (MO) Plant Materials Center.

Spring seedings - during April and May - of big bluestem are preferred. It should be seeded in fine, firm seedbeds free of competition. Seedbeds should be firmed with a roller prior to drilling or broadcasting seed. If the seed is planted with the broadcast method, it also should be rolled afterward to help cover the seed. Seed that is drilled should be planted one-fourth inch deep. Seven pounds of pure live seed per acre are recommended.

No-tillage seedings in closely grazed sod also have been successful where control of sod is accomplished with proper herbicides. In addition, early spring plantings (March and April) and fall dormant seedings (November and December) have been successful. They also provide weed and soil erosion control.

Special rangeland drills capable of seeding light, fluffy seed must be used to plant unprocessed big bluestem seed. Seed processed by removing the appendages with a debearder may be planted with a wide variety of commonly-used, grass-seeding equipment.

Controlling weeds at seeding time is important because grass establishment and survival can be suppressed by weed competition for moisture and sunlight. Several brands of atrazine have been cleared for weed control with big bluestem. Label rates and conditions should be understood and strictly followed to prevent severe seedling mortality.

Fertilizer applied during the seeding year usually does not increase stand density, but will increase plant vigor. To limit weed growth, nitrogen should not be applied until mid-July, and then only on stands with limited weed competition. Not more than 30 pounds of nitrogen per acre should be applied at this time.

Stand densities of 1.5 to two established plants per square foot in the spring of the second year is adequate for hay yields or pasture.

Annual fertilizer applications of 60 pounds nitrogen and 30 pounds each of phosphorus and potassium per acre usually are adequate for maximum yields. Rates should be adjusted in accordance with soil tests.

Weeds in established stands of big bluestem can be minimized by maintaining plant vigor and density. Occasional use of approved herbicides reduces competition and helps restore plant vigor to an overgrazed stand. Burning plant residues at initiation of spring growth decreases competition and stimulates big bluestem growth.

Big bluestem may be grazed when it reaches a height of 14 to 16 inches. It can be grazed continuously as long as a minimum height of eight to 12 inches is maintained. Of the three most common warm-season grasses, big bluestem matures later than switch grass and earlier than Indian grass. It provides excellent forage from mid to late summer. A fall height of 12 inches should be attained before frost. It may be grazed to a height of six to eight inches after frost. The winter stubble is necessary to provide insulation.

To obtain maximum hay quality and quantity, hay cuttings should be made when big bluestem is at boot stage, in mid-to-late July.

For more information about big bluestem, contact the local Soil Conservation Service office. It is listed in the telephone directory under "U.S. Government."

© United States Department of Agriculture

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