- Carduus acanthoides is an annual or biennial herbaceous plant that grows to 5 ft. (1.5 m) tall.
- This thistle may exceed two meters in height and can form weedy monotypic stands. The stem and foliage are spiny and sometimes woolly.
- Flowering occurs from May to August. The flower heads are reddish-purple in color and up to 1 in. (2.5 cm) in diameter. Flower stems are branched with spiny wings extending to the flower heads.
- Seeds are oblong, striate, and slightly curved.
- Ecological Threat
- Carduus acanthoides infests open, disturbed areas such as pastures, roadsides, and railroad right-of-ways. It can form thick stands that reduce the forage potential of pastures and suppress the growth of desirable vegetation.
- Biological Control of Invasive Plants in the Eastern United States - USDA Forest Service
- Carduus acanthoides - Burke Museum of Natural History and Culture
- Weed Field Guide - USDA Forest Service
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EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org
Invasive Listing Sources
- Arizona Noxious Weeds
- California Invasive Plant Council
- California Noxious Weeds
- Colorado Noxious Weeds
- Faith Campbell, 1998
- Great Lakes Early Detection Network
- Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
- Idaho Noxious Weeds
- Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
- John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
- Maryland Noxious Weeds
- Michigan Noxious Weeds
- Mid-Atlantic Exotic Pest Plant Council, 2005
- Minnesota Noxious Weeds
- Nebraska Noxious Weeds
- New Jersey Department of Agriculture, Division of Plant Industry, 2004
- Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
- North Carolina Noxious Weeds - Class B
- Oregon Noxious Weeds
- Pacific Northwest Exotic Pest Plant Council, 1998
- South Dakota Noxious Weeds
- Tennessee Exotic Pest Plant Council
- Washington Noxious Weeds
- WeedUS - Database of Plants Invading Natural Areas in the United States
- West Virginia Noxious Weeds
- Wisconsin's Invasive Species Identification, Classification and Control Rule
- Wyoming Noxious Weeds
|Common Name Reference:|| USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|
|Scientific Name Reference:||USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|