musk thistle

Asterales > Asteraceae > Carduus nutans L.
Synonym(s): nodding plumeless thistle, nodding thistle, bristle thistle

Musk thistle is an herbaceous, biennial plant that grows to 6 ft. (1.8 m) tall. It has become a serious invader of open lands throughout the continental United States. It can be recognized by its showy, red-purple flowers and very spiny stem and leaves. Flowering occurs from June to September. The large, disk-shaped, terminal flower heads droop when mature. Musk thistle invades a variety of disturbed areas. Pastures are particularly at risk because musk thistle is unpalatable to livestock. Once established it can spread rapidly due to high seed production (as much as 120,000 seed per plant). Musk thistle is native to Western Europe and was accidentally introduced into the United States in the early 1900s.


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; basal rosette
Loke T. Kok, Virginia Polytechnic Institute and State University, Bugwood.org
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Plant(s); lower stem
Dan Tenaglia, Missouriplants.com, Bugwood.org
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Plant(s); upper stem
Dan Tenaglia, Missouriplants.com, Bugwood.org
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Feature(s); Stem and foliage
Mary Ellen (Mel) Harte, , Bugwood.org
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Flower(s);
USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org
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Plant(s);
James H. Miller, USDA Forest Service, Bugwood.org
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Flower(s);
James R. Allison, Georgia Department of Natural Resources, Bugwood.org
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Flower(s);
Ricky Layson, Ricky Layson Photography, Bugwood.org
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Flower(s); June
James H. Miller, USDA Forest Service, Bugwood.org
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Stem(s); June
James H. Miller, USDA Forest Service, Bugwood.org
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Flower(s);
Ricky Layson, Ricky Layson Photography, Bugwood.org
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Flower(s); Ready to set seed. Montana
Wendy VanDyk Evans, , Bugwood.org
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Flower(s);
Steve Dewey, Utah State University, Bugwood.org
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Plant(s);
Steve Dewey, Utah State University, Bugwood.org
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Plant(s);
Mary Ellen (Mel) Harte, , Bugwood.org
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Plant(s);
Steve Dewey, Utah State University, Bugwood.org
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Flower(s);
Steve Dewey, Utah State University, Bugwood.org
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Plant(s);
Vince Belleci, , Bugwood.org
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Infestation;
Norman E. Rees, USDA Agricultural Research Service, Bugwood.org
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Infestation;
Steve Dewey, Utah State University, Bugwood.org
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Infestation;
Vince Belleci, , Bugwood.org
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Infestation; A pile of fill dirt left over winter. The following spring, the pile was covered in musk thistles.
Kris Johnson, Great Smoky Mountains National Park, 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: 554.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
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Invasive Reference(s):

Check Invasive.org for most current lists.
  • California - Noxious Weed Law
  • Colorado - Noxious Weed Law
  • Georgia - EPPC list
  • Illinois - Noxious Weed Law
  • Kansas - Noxious Weed Law
  • Maryland - Noxious Weed Law
  • Michigan - Noxious Weed Law
  • Minnesota - Noxious Weed Law
  • Missouri - Noxious Weed Law
  • Nebraska - Noxious Weed Law
  • New Mexico - Noxious Weed Law
  • Nevada - Noxious Weed Law
  • North Carolina - Noxious Weed Law
  • North Dakota - Noxious Weed Law
  • Ohio - Noxious Weed Law
  • Oklahoma - Noxious Weed Law
  • Oregon - Noxious Weed Law
  • Pennsylvania - Noxious Weed Law
  • South Carolina - EPPC List
  • South Dakota - Noxious Weed Law
  • Tennessee - EPPC List
  • Utah - Noxious Weed Law
  • Virginia - Invasive Alien Plant Species
  • Washington - Noxious Weed Law
  • West Virginia - Noxious Weed Law
  • Wyonming - Noxious Weed Law
  • Mid-Atlantic - EPPC List


External Links


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