Red-top is a naturalized perennial grass often used for erosion control as it can form dense tufts. It has a rhizomatous root system, but does not send out stolons.
The stems are usually erect, from 4 to 48 inches high but are sometimes bent at he base such that lower stem nodes can take root.
Leaves are narrow, flat, about 3/8 inch wide and short, up to 4 inches long. Ligules are longer than wide, with the back side usually rough but sometimes smooth. The Ligule tops are rounded to truncate.
The inflorescence is pyramidal in shape, less than 1/2 the length of the stem, branches spreading, slightly rough, with the spikelets found on the outer half of the branch. The array is reddish in color and can be up to 10 inches long. It matures early. The spikelets are narrowly ovate to lanceolate, green and usually strongly tinged with purple. The glumes are sub-equal, lemmas are 3 to 5 veined but not always conspicuous, usually without awns. Anthers number 3.
Habitat: Red-top is found in much of the Great Plains and it can tolerate wet or dry conditions but is generally found in areas where there is moisture or recent moisture such as after flooding.
Names: The genus Agrostis, is a Greek word for a certain grass. The species, gigantea, means unusually tall or large, referring to the large flowering panicle being almost half the plant height. The author name for the plant classification - ‘Roth’ is for Albrecht Wilhelm Roth (1757-1834) German botanist who published his research and was later associated with the University of Jena Botanical Institute.
Comparisons: A confusing species is A. stolonifera, which has a somewhat smaller panicle and the root system forms stolons that are either on the surface or just under, which root at the nodes, forming colonies.
Above: Plant photo ©Anna Gardner, Iowa State University. Drawing by Agnes Chase from Norman C. Fassett's Grasses of Wisconsin
Below: Spikelets in flower. Leaf sheath and ligule area.
Below: Spikelet branches of the panicle.
Below: Underside of the leaf blade and the root system.
Notes: This grass, while not native, was naturalized in the Garden. Eloise Butler catalogued it in her early Garden Records. Red-top is not native but widely naturalized throughout North America. In Minnesota it is found in all but 11 widely scattered counties.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"