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 accidently 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

  • Weed of the Week - USDA Forest Service
    http://www.na.fs.fed.us/fhp/invasive_plants/weeds/cogongrass.pdf - Nov 7, 2006

Selected Images

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Number:0908094
Description: Plant(s); note the flowering plant at the center back
Photographer:Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services
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Number:2186086
Description: Feature(s); Plant Base
Photographer:Richard Carter, Valdosta State University
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Number:5362528
Description: Root(s);

Rhizome

Photographer:Carey Minteer, University of Georgia
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Number:2132088
Description: Feature(s); Leaf-collar region
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:2132087
Description: Foliage; Showing off-center midrib
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:1334120
Description: Feature(s); The whitish midribs are often off-center. Mitchell County, GA
Photographer:Chris Evans, River to River CWMA
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Number:5302013
Description: Plant(s);
Photographer:Chris Evans, River to River CWMA
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Number:5344085
Description: Root(s);
Photographer:Chuck Bargeron, University of Georgia
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Number:2132089
Description: Feature(s); Sharp-pointed rhizome
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:1380063
Description: Feature(s); Segmented rhizomes with outer covering intact (bottom) and removed (top)
Photographer:Chris Evans, River to River CWMA
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Number:1380059
Description: Feature(s); Ligule
Photographer:Chris Evans, River to River CWMA
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Number:1380060
Description: Feature(s); Collar region
Photographer:Chris Evans, River to River CWMA
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Number:2131097
Description: Flower(s);
Photographer:Chris Evans, River to River CWMA
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Number:2132091
Description: Flower(s);
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:2131084
Description: Fruit(s);
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:2186087
Description: Flower(s);
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:2131087
Description: Flower(s);
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:1299003
Description: Infestation;

Cogongrass infestation in Mississippi Pine Plantation.

Photographer:Charles T. Bryson, USDA Agricultural Research Service
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Number:1237047
Description: Infestation; Large infestation
Photographer:Wilson Faircloth, USDA Agricultural Research Service
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Number:1380040
Description: Infestation;
Photographer:Chris Evans, River to River CWMA
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Number:1380045
Description: Infestation;
Photographer:Chris Evans, River to River CWMA
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Number:1380049
Description: Infestation;
Photographer:Chris Evans, River to River CWMA
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Number:5371431
Description: Control;

Same area as this image after 3 years of treatment with glyphosate.

Photographer:Carey Minteer, University of Georgia
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Number:2131086
Description: Infestation;
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:2131089
Description: Dispersal;

Stuck in radiator of tractor

Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:2132092
Description: Infestation;
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:5345041
Description: Infestation;
Photographer:David J. Moorhead, University of Georgia
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Number:0016381
Description: Infestation; Herbicide test plots bare in 20-year old stand
Photographer:James H. Miller, USDA Forest Service
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Number:1237048
Description: Infestation; Roadside infestation
Photographer:Wilson Faircloth, USDA Agricultural Research Service
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Number:2131085
Description: Infestation;
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:2131090
Description: Infestation; Small infestation in woods
Photographer:Mark Atwater, Weed Control Unlimited, Inc.
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Number:2132052
Description: Infestation;
Photographer:David J. Moorhead, University of Georgia
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Number:2132002
Description: Infestation;
Photographer:Chris Evans, River to River CWMA
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Number:2132046
Description: Infestation;
Photographer:David J. Moorhead, University of Georgia
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Number:2155053
Description: Infestation;
Photographer:John D. Byrd, Mississippi State University
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Number:2155058
Description: Control; Deep disking
Photographer:John D. Byrd, Mississippi State University
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Number:2155059
Description: Feature(s); Rhizomes
Photographer:John D. Byrd, Mississippi State University
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Number:3970058
Description: Feature(s); a severe infestation in a longleaf pine upland in central Florida
Photographer:James R. Meeker, USDA Forest Service
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Number:1119111
Description: Infestation; In Winter
Photographer:Chris Evans, River to River CWMA
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Number:5344082
Description:Red Baron
Photographer:Mark Crosby, University of Georgia
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Number:1237063
Description: Plant(s); Planted "Red Baron" variety
Photographer:David Teem, Auburn University
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Number:2308083
Description: Infestation; Distinctive circular infestations in harvest stand.
Photographer:Greg Leach, International Paper
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Number:1499084
Description: Infestation;
Photographer:Tony Pernas, USDI National Park Service
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Number:5078025
Description: Prescribed Fire; Prescribed fire to remove thatch before herbicide application
Photographer:David J. Moorhead, University of Georgia
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Number:2132048
Description: Diagram or Graphic;
Photographer:David J. Moorhead, University of Georgia
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External Links

Invasive Reference(s)

Subject Reference(s)

  • USDA, NRCS. 2001. The PLANTS Database, Version 3.1, National Plant Data Center, Baton Rouge, LA 70874-4490 USA. - http://plants.usda.gov/