Russian knapweed |
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| Asterales > Asteraceae > Acroptilon repens (L.) DC.
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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 0.5 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 1900s. This species can cause chewing disease in horses. |
Identification, Biology, Control and Management Resources
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Selected Images from Invasive.org
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Seedling(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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Flower(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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Feature(s); Bud stage with detached bracts
Steve Dewey, Utah State University, Bugwood.org
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Plant(s);
Norman E. Rees, USDA Agricultural Research Service, Bugwood.org
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Plant(s);
Norman E. Rees, USDA Agricultural Research Service, Bugwood.org
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Plant(s);
Steve Dewey, Utah State University, Bugwood.org
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Infestation;
Norman E. Rees, USDA Agricultural Research Service, Bugwood.org
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Fruit(s);
Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org
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Invasive Reference(s):
Check Invasive.org for most current lists.
- Alaska - Noxious Weed Law
- Arizona - Noxious Weed Law
- California - Noxious Weed Law
- Colorado - Noxious Weed Law
- Kansas - Noxious Weed Law
- Michigan - Noxious Weed Law
- Minnesota - Noxious Weed Law
- Montana - Noxious Weed Law
- New Mexico - Noxious Weed Law
- Nevada - Noxious Weed Law
- North Dakota - Noxious Weed Law
- Oregon - Noxious Weed Law
- South Carolina - Noxious Weed Law
- South Dakota - Noxious Weed Law
- Texas - Invasive Plant List
- Utah - Noxious Weed Law
- Washington - Noxious Weed Law
- Wyonming - Noxious Weed Law
- Invasive Plants: Western North America
- Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species
External Links
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