Andropogon gerardii

big bluestem, bluejoint, turkeyfoot
Family

Poaceae

Leaf Arrangement

alternate

Leaf Attachment

sheathing

Leaf Type

simple

Leaf Shape

linear

Growth Form

graminoid

Flower Color

brown, green, purple

Flower Month

July - October

Height (meters)

1.0 - 3.0

Milky Sap

No

Armed/Unarmed

Unarmed

Origin

native

Lifespan

perennial

Growing Season

Warm season


Wetland Class

FAC

Prairie Coefficient of Conservatism

9

Field Characters

The inflorescence has 3 finger-like rames each 2-4" long (shaped somewhat like a "turkey foot"). The young shoots are somewhat flattened at the base, and the lower leaves are usually covered with long silky hair, particularly at the base. The plants grow in large clumps and are very leafy. The lower leaves curl when dry and pull off easily from the base. The culms are gray-blue when young and develop a reddish bronze cast between the nodes at maturity. The bluestems have pithy stems like corn, while most other grasses have hollow stems. Without seed heads, Andropogon gerardii resembles Florida paspalum, but can usually be distinguished by such characters as the leaf blades which narrow slightly near the collar, widening gradually toward the midsection while the lower blade of Florida paspalum has a relatively constant width. The inner surface of the sheath of big blue is browinsh to bronze, as is its ligule, while that of Florida paspalum is green.

Cultural Information

Big bluestem is widely planted from seed in the United States. Seed is produced commercially in pure stands and in mixed stands with other tall grasses and is harvested with a combine. A number of varieties or cultivars were selected by the Soil Conservation Service, and most are available today from seed suppliers (see below). Seed from local ecotypes can be harvested from remnants or restorations from October-November and germinates with no treatment when planted fresh. Seed from isolated populations on prairie remnants in Louisiana has tested at less than 10% viability. Planting ramets from several populations in one area has been shown to increase seed set and viability. Viability and seed set has also been shown to increase after the plants have been burned. Clumps may be divided, the soil washed from their roots, and the rhizomes cut into pieces small enough to fit into 6" pots. We have done this with good success in the fall, when Big Bluestem is easily recognized. Commercial seed as a purity of 40% and a germination rate of 60%. There are 165,000 - 200,000 seed/lb and it should be planted at a rate of 7-15 lbs/acre. Seed germination is improved by cold/moist stratification (Steffen 1997). Varieties: 'Bonilla' - orginates from Bonilla, South Dakota. It is recommended for use in North Dakota, South Dakota, and Minnesota. It exhibits early maturity and early winter hardiness. 'Champ' - originates from Iowa and northern Nebraska. It was developed from interbreeding big bluestem and sand bluestem. This is an early maturing cultivar recommended for use from Nebraska south into Kansas, and eastward on favorable sites. 'Kaw' - originates from the Flint Hills of Kansas. This is a tall, leafy, late maturing cultivar recommended for use from central Nebraska south through Oklahoma. 'Pawnee' - originates from Pawnee County, Nebraka. This is a late maturing cultivar recommended for use from central Nebraska south through Oklahoma. 'Rountree' - originates from west-central Iowa. This cultivar is resistant to leaf rust and has high forage production. It is recommended for use throughout Missouri, Iowa, and southern Illinois. 'NDG-4' - is being developed from seed collected in North Dakota for possible use throughout the Northern Great Plains. Seeds collected from remnant populations averaged approximately 213,000 seeds/lb.

Animal Use

Important forage for deer and livestock. Because of its high yield and palatability, big bluestem is one of the most important native forage grasses of the North American tallgrass prairie. It is relished by livestock and often eaten in preference to other grasses in the mixture. Others include little bluestem, indiangrass, and switchgrass (Gould 1975). Attracts little wood satyr and checkered skipper butterflies. When allowed to mature it provides outstanding brood cover for wildlife. The following information for the genus Andropogon: Animals that eat its seed: Prairie chicken, Wild turkey, Chipping sparrow, Small Mammals, Meadow mouse. Animals that eat the plant: White-tailed deer, meadow mouse (Martin et al. 1951).

Natural History

A giant grass and one of the prairie dominates responsible for the name "tallgrass prairie." It grows on the best prairie soils through most of its range and is tolerant of all moisture levels. In the Midwest Big Bluestem dominates valleys and moist areas. On hill tops and dry areas it gives way to little bluestem (Weaver and Fitzpatrick 1934). It is unequaled as forage in both quality and quantity. It is very palatable to cattle and has been grazed out of existence over most of its range. Its palatability drops, however, during dormancy. If it is not grazed to less than 6-8 inches, it can regrow quickly. When grazed to less than this height it decreases and is replaced by less productive grasses. If not grazed shortly before the first frost, root storage is improved. It may be grazed after senescence without harm (Philips Petroleum Company 1955). The scientific name "Andropogon" is from two Greek words "Aner" meaning man, and "pogon" meaning beard. The common name "beardgrass" given to bluestems corresponds to their scientific name. Big Bluestem is reported to be cross-fertilized (U.S.D.A. 1948). Because it evolved in an environment subjected to frequent fires, big bluestem is well adapted to fire. When the aboveground vegetation burns away, new growth occurs from the rhizomes. Spring burns result in vigorous new growth while in summer the plants regrow using the limited resources in the rhizomes. In a normal year, a spring burn results in vigorous growth of big bluestem due to increased nutrients and sunlight. However, because burned areas loose more soil moisture due to evaporation than unburned areas, they are more sensitive to drought.

Habitat

Moist or dry places, prairies.