johnsongrass

Cyperales > Poaceae > Sorghum halepense (L.) Pers.

Johnsongrass is a tall (up to 8 ft. [2.4 m]), rhizomatous, perennial grass that invades open areas throughout the United States. The 2 ft. (0.6 m) long, lanceolate leaves are arranged alternately along a stout, hairless, somewhat upward branching stem and have distinct, white midribs. Flowers occur in a loose, spreading, purplish panicle. Johnsongrass is adapted to a wide variety of habitats including open forests, old fields, ditches and wetlands. It spreads aggressively and can form dense colonies which displace native vegetation and restrict tree seedling establishment. Johnsongrass has naturalized throughout the world, but it is thought to be native to the Mediterranean region. It was first introduced into the United States in the early 1800s as a forage crop.


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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Seedling(s);
Steve Dewey, Utah State University, Bugwood.org
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Feature(s); Roots
Steve Dewey, Utah State University, Bugwood.org
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Feature(s); Rhizomes
Steve Dewey, Utah State University, Bugwood.org
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Feature(s); Roots
Chris Evans, River to River CWMA, Bugwood.org
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Feature(s); Stem
Chris Evans, River to River CWMA, Bugwood.org
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Feature(s); Leaf collar region
Steve Dewey, Utah State University, Bugwood.org
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Feature(s); Ligule
Steve Dewey, Utah State University, Bugwood.org
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Feature(s); Ligule
Chris Evans, River to River CWMA, Bugwood.org
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Foliage;
Chris Evans, River to River CWMA, Bugwood.org
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Flower(s); July. Photo from Forest Plants of the Southeast and Their Wildlife Uses by J.H. Miller and K.V. Miller, published by The University of Georgia Press in cooperation with the Southern Weed Science Society.
James H. Miller, USDA Forest Service, Bugwood.org
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Plant(s);
Barry Fitzgerald, USDA Agricultural Research Service, Bugwood.org
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Fruit(s); Ventral view of spikelets with pedicel and rachis segment
Julia Scher, USDA APHIS PPQ, Bugwood.org
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Fruit(s);
Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org
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Flower(s);
Jil M. Swearingen, USDI National Park Service, Bugwood.org
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Plant(s);
Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org
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Plant(s);
Chris Evans, River to River CWMA, Bugwood.org
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Plant(s);
Steve Dewey, Utah State University, Bugwood.org
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Infestation; Invasive plants complicate roadise begetation management programs, create safety hazards by obscuring visibility and increasing the intensity of roadsidefires, and provide seed sources for infestation of adjacent fields.
Bonnie Harper-Lore, Federal Highway Administration, Bugwood.org
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Infestation; Large infestation in September
David J. Moorhead, University of Georgia, Bugwood.org
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Infestation;
Steve Dewey, Utah State University, Bugwood.org
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Diagram or Graphic; Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 1: 121.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
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Diagram or Graphic; Hitchcock, A.S. (rev. A. Chase). 1950. Manual of the grasses of the United States. USDA Misc. Publ. No. 200. Washington, DC.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
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Invasive Reference(s):

Check Invasive.org for most current lists.
  • Alabama - IPC List
  • Arkansas - Noxious Weed Law
  • California - Noxious Weed Law
  • Colorado - Noxious Weed Law
  • Delaware - Noxious Weed Law
  • Georgia - EPPC list
  • Illinois - Noxious Weed Law
  • Indiana - Noxious Weed Law
  • Kansas - Noxious Weed Law
  • Kentucky - EPPC List
  • Kentucky - Noxious Weed Law
  • Maryland - Noxious Weed Law
  • Michigan - Noxious Weed Law
  • Mississippi - 10 Worst Invasive Weeds
  • Missouri - Noxious Weed Law
  • Nevada - Noxious Weed Law
  • Ohio - Noxious Weed Law
  • Oregon - Noxious Weed Law
  • Pennsylvania - Noxious Weed Law
  • South Carolina - EPPC List
  • South Dakota - Noxious Weed Law
  • Tennessee - EPPC List
  • Texas - Invasive Plant List
  • Utah - Noxious Weed Law
  • Virginia - Invasive Alien Plant Species
  • Washington - Noxious Weed Law
  • West Virginia - Noxious Weed Law
  • Mid-Atlantic - EPPC List
  • Invasive Plants: Western North America
  • Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species
  • Invasive Plants of the Upper Midwest
  • Invasive Plant Atlas of the Mid-South


External Links


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USDA Forest Service Bugwood University of Georgia