redtop USDA PLANTS Symbol: AGGI2
U.S. Nativity: Exotic
Habit: Grass or Grasslike
Agrostis gigantea Roth

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Taxonomic Rank: Liliopsida: Cyperales: Poaceae
Native Range: Eurasia (BAIL);

Agrostis gigantea is a perennial grass that makes a coarse turf and grows to 2-3 ft. (0.6-0.9 m) tall.
Leaves are bluish green or greyish blue, narrow, sharp and about 0.4 in. (0.95 cm) wide and 8 in. (20.3 cm) long. The stems are slender, growing to 30-40 in. (76.2-101.6 cm) tall.
The inflorescence is pyramidal and reddish in color--hence the common name of redtop. Flowers are yellow in color and bloom mid-spring.
Fruit and seeds begin ripening in early summer. Seeds are very small and brown in color. Agrostis gigantea grows rapidly after seeding.
Ecological Threat
Agrostis gigantea occurs in areas with shallow water, in wet meadows, in grasslands, and along stream banks. It is native to Eurasia.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at

Plant(s); whole plant with inflorescences
Dave Powell, USDA Forest Service (retired),
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit

State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.

U.S. National Parks where reported invasive:
Colonial National Historical Park (Virginia)

Invasive Listing Sources:
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
Mid-Atlantic Exotic Pest Plant Council, 2005