cogongrass

Cyperales > Poaceae > Imperata cylindrica (L.) Beauv.
Synonym(s): cogon grass, alang-alang

Cogongrass is a perennial colony-forming grass which can grow up to 6 ft. (1.8 m) tall. Leaves have an off-center, whitish midrib and finely serrated margins. Leaves are up to 6 ft. (1.8 m) long, 0.5-0.75 in. (1.3-1.9 cm) wide, stiff, and have a sharp, pointed apex. Rhizomes are whitish, branched, scaly and sharp at the tips. Cogongrass is best identified in the spring by the large fuzzy panicle of flowers and seeds, giving the plant a cottony or silky look. Flower heads are 2-8 in. (5.1-20.3 cm) long, silvery-white and cylindrical. Cogongrass is an extremely aggressive invader with the capability of invading a range of sites. It forms dense, usually circular infestations that exclude all other vegetation. Cogongrass is native to Southeast Asia and was accidentally introduced into the southeast United States in packing material in the early 1900s. It was also intentionally introduced for erosion control and livestock forage.


Identification, Biology, Control and Management Resources

  • Weeds of the Week - USDA Forest Service, Northeastern Area, Forest Health Protection

Selected Images from Invasive.org

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Plant(s); note the flowering plant at the center back
Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org
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Feature(s); Plant Base
Richard Carter, Valdosta State University, Bugwood.org
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Root(s); Rhizome
Carey Minteer, University of Georgia, Bugwood.org
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Feature(s); Leaf-collar region
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Foliage; Showing off-center midrib
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Feature(s); The whitish midribs are often off-center. Mitchell County, GA
Chris Evans, River to River CWMA, Bugwood.org
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Plant(s);
Chris Evans, River to River CWMA, Bugwood.org
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Root(s);
Chuck Bargeron, University of Georgia, Bugwood.org
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Feature(s); Sharp-pointed rhizome
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Feature(s); Segmented rhizomes with outer covering intact (bottom) and removed (top)
Chris Evans, River to River CWMA, Bugwood.org
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Feature(s); Ligule
Chris Evans, River to River CWMA, Bugwood.org
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Feature(s); Collar region
Chris Evans, River to River CWMA, Bugwood.org
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Flower(s);
Chris Evans, River to River CWMA, Bugwood.org
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Flower(s);
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Fruit(s);
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Flower(s);
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Flower(s);
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Infestation; in pine reforestation
Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org
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Infestation; Large infestation
Wilson Faircloth, USDA Agricultural Research Service, Bugwood.org
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Infestation;
Chris Evans, River to River CWMA, Bugwood.org
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Infestation;
Chris Evans, River to River CWMA, Bugwood.org
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Infestation;
Chris Evans, River to River CWMA, Bugwood.org
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Control; Same area as previous image after 3 years of treatment with glyphosate.
Carey Minteer, University of Georgia, Bugwood.org
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Infestation;
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Dispersal; Stuck in radiator of tractor
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Infestation;
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Infestation;
David J. Moorhead, University of Georgia, Bugwood.org
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Infestation; Herbicide test plots bare in 20-year old stand
James H. Miller, USDA Forest Service, Bugwood.org
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Infestation; Roadside infestation
Wilson Faircloth, USDA Agricultural Research Service, Bugwood.org
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Infestation;
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Infestation; Small infestation in woods
Mark Atwater, Weed Control Unlimited, Inc., Bugwood.org
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Infestation;
David J. Moorhead, University of Georgia, Bugwood.org
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Infestation;
Chris Evans, River to River CWMA, Bugwood.org
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Infestation;
David J. Moorhead, University of Georgia, Bugwood.org
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Infestation;
John D. Byrd, Mississippi State University, Bugwood.org
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Control; Deep disking
John D. Byrd, Mississippi State University, Bugwood.org
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Feature(s); Rhizomes
John D. Byrd, Mississippi State University, Bugwood.org
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Feature(s); a severe infestation in a longleaf pine upland in central Florida
James R. Meeker, USDA Forest Service, Bugwood.org
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Infestation; In Winter
Chris Evans, River to River CWMA, Bugwood.org
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Mark Crosby, University of Georgia, Bugwood.org
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Plant(s); Planted "Red Baron" variety
David Teem, Auburn University, Bugwood.org
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Infestation; Distinctive circular infestations in harvest stand.
Greg Leach, International Paper, Bugwood.org
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Infestation;
Tony Pernas, USDI National Park Service, Bugwood.org
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Prescribed Fire; Prescribed fire to remove thatch before herbicide application
David J. Moorhead, University of Georgia, Bugwood.org
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Diagram or Graphic;
David J. Moorhead, University of Georgia, Bugwood.org
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Invasive Reference(s):

Check Invasive.org for most current lists.
  • Federal Noxious Weed List
  • Alabama - IPC List
  • Arkansas - Noxious Weed Law
  • California - Noxious Weed Law
  • Florida - EPPC list
  • Georgia - EPPC list
  • Mississippi - Noxious Weed Law
  • Mississippi - 10 Worst Invasive Weeds
  • North Carolina - Noxious Weed Law
  • Oregon - Noxious Weed Law
  • South Carolina - EPPC List
  • South Carolina - Noxious Weed Law
  • Tennessee - Noxious Weed Law
  • Texas - Invasive Plant List
  • Vermont - Noxious Weed Law
  • Virginia - Invasive Alien Plant Species
  • Mid-Atlantic - EPPC List
  • Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species
  • Invasive Plant Atlas of the Mid-South


External Links


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