bull thistle

Asterales > Asteraceae > Cirsium vulgare (Savi) Ten.
Synonym(s): common thistle, spear thistle

Bull thistle is an annual or biennial, herbaceous plant that invades disturbed areas throughout the United States. The spiny, spreading, winged stems are up to 7 ft. (2.1 m) tall. Leaves are 3-12 in. (7.6-30.5 cm) long, lance-shaped and very hairy. Flowers develop, at the apex of the plant, from June to September. The purple flower heads are 1.5-2 in. (3.8-5.1 cm) in diameter and 1-2 in. (2.5-5.1 cm) long with narrow, spine-tipped bracts. Bull thistle can invade almost any type of disturbed area, such as forest clearcuts, riparian areas and pastures. Plants can form dense thickets, displacing other vegetation. The spiny nature of the plant renders it unpalatable to wildlife and livestock and reduces the forage potential of pastures. Bull thistle is native to Europe, western Asia, and northern Africa. It is thought to have been introduced to the eastern United States during colonial times and the western United States in the late 1800s. It is currently found in all 50 states.


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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Foliage;
Richard Old, XID Services, Inc., Bugwood.org
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Foliage; Basal rosette
Michael Shephard, USDA Forest Service, Bugwood.org
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Foliage; Basal rosette
Michael Shephard, USDA Forest Service, Bugwood.org
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Plant(s);
Richard Old, XID Services, Inc., Bugwood.org
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Foliage;
Steve Dewey, Utah State University, Bugwood.org
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Foliage;
Richard Old, XID Services, Inc., Bugwood.org
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Foliage;
Dan Tenaglia, Missouriplants.com, Bugwood.org
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Plant(s); stem
Dan Tenaglia, Missouriplants.com, Bugwood.org
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Feature(s); Spines
Steve Dewey, Utah State University, Bugwood.org
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Flower(s); habit
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
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Flower(s); flowers
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
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Flower(s); flower
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
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Flower(s); close up
Loke T. Kok, Virginia Polytechnic Institute and State University, Bugwood.org
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Flower(s);
Britt Slattery, U.S. Fish and Wildlife Service, Bugwood.org
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Fruit(s); seeds
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
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Fruit(s);
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
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Plant(s); large mature plant on timber harvest area
Dave Powell, USDA Forest Service, Bugwood.org
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Plant(s); habit
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
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Plant(s); habit and flowers
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
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Plant(s); in flower
Steve Dewey, Utah State University, Bugwood.org
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Competition; under dead fir killed by budworm. Swale Creek, Under dead fir killed by western spruce budworm (Choris├é┬Čtoneura occidentalis); Swale Creek, Heppner Ranger District, Umatilla National Forest, northeastern Oregon
Dave Powell, USDA Forest Service, Bugwood.org
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Fruit(s);
Steve Hurst, USDA NRCS PLANTS Database, 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. 3: 549.
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
  • California - Invasive Plant Inventory
  • Colorado - Noxious Weed Law
  • Georgia - EPPC list
  • Iowa - Noxious Weed Law
  • Maryland - Noxious Weed Law
  • Michigan - Noxious Weed Law
  • Minnesota - Noxious Weed Law
  • New Mexico - Noxious Weed Law
  • Oregon - Noxious Weed Law
  • Pennsylvania - Noxious Weed Law
  • Rhode Island - Noxious Weed Law
  • South Carolina - EPPC List
  • Tennessee - EPPC List
  • Texas - Invasive Plant List
  • Virginia - Invasive Alien Plant Species
  • Washington - Noxious Weed Law
  • Mid-Atlantic - EPPC List
  • Invasive Plants: Western North America
  • Invasive Plants of the Upper Midwest


External Links


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