| Russian knapweed |
USDA PLANTS Symbol: ACRE3 USDA ARS GRIN: 103782 ITIS: 36459 NAPIS: PBFARBI |
| Acroptilon repens (L.) DC. | |
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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae |
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| Synonym(s): hardheads | |
Russian knapweed is a perennial forb that can grow to 3 ft. (1 m) in height. Stems originate from a basal rosette of leaves. The rosette leaves can be unlobed to very lobed and are 2-4 in. (5-10 cm) long. Stem leaves are oblong, pinnately lobed to entire and up to 6 in. (15.2 cm) in length at the base of the stem and become smaller and less lobed toward the top. In summer to fall Russian knapweed produces flowers that are pink to purple and turn straw colored as they mature. The flower heads are approximately ½ in (1.2 cm) in diameter and urn shaped. Fruits (achenes) are ivory-colored with a tuft of hair that falls off at maturity. Russian knapweed is native to Eurasia and was introduced into the United States in the early 1900’s. This species can cause chewing disease in horses. |
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Identification, Biology, Control and Management Resources
- Federal Noxious Weed Disseminules of the U.S. - USDA-APHIS
- Element Stewardship Abstract - The Nature Conservancy
- Know Your Knapweeds - North Dakota State University
| Selected Images from Invasive.org | View All Images at Invasive.org |
 Seedling(s); Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Feature(s); Bud stage with detached bracts Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Norman E. Rees, USDA Agricultural Research Service, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Norman E. Rees, USDA Agricultural Research Service, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Infestation; Norman E. Rees, USDA Agricultural Research Service, Bugwood.org Additional Resolutions & Image Usage |
 Fruit(s); Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org Additional Resolutions & Image Usage |
Taxonomic References:
- USDA, NRCS. 2001. The PLANTS Database, Version 3.1, National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Invasive Listing Sources:
- Faith Campbell, 1998. Plants that Hog the Garden: Invasive Plants in the United States. Fine Gardening Online
- 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.
- 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.
- Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
- Pacific Northwest Exotic Pest Plant Council, 1998
- WeedUS - Database of Plants Invading Natural Areas in the United States
- Alaska Noxious Weeds
- Arizona Noxious Weeds
- California Invasive Plant Council
- California Noxious Weeds
- Colorado Noxious Weeds
- Iowa Noxious Weeds
- Idaho Noxious Weeds
- Kansas Noxious Weeds
- Michigan Noxious Weeds
- Minnesota Noxious Weeds
- Montana Noxious Weeds
- North Dakota Noxious Weeds
- New Mexico Noxious Weeds
- Nevada Noxious Weeds
- Oregon Noxious Weeds
- South Carolina Noxious Weeds
- South Dakota Noxious Weeds
- Utah Noxious Weeds
- Washington Noxious Weeds
- Wyoming Noxious Weeds
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