Russian knapweed

Asterales > Asteraceae > Acroptilon repens (L.) DC.
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.

Identification, Biology, Control and Management Resources

  • Know Your Knapweeds - North Dakota State University
    http://www.ext.nodak.edu/extpubs/plantsci/weeds/w1146.pdf - Apr 18, 2005

Selected Images

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Number:1459259
Description: Seedling(s);
Photographer:Steve Dewey, Utah State University
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Number:1459258
Description: Plant(s);
Photographer:Steve Dewey, Utah State University
 Additional Resolutions and Image Usage
 
Number:1459261
Description: Flower(s);
Photographer:Steve Dewey, Utah State University
 Additional Resolutions and Image Usage
 
Number:1459265
Description: Flower(s);
Photographer:Steve Dewey, Utah State University
 Additional Resolutions and Image Usage
 
Number:1459264
Description: Feature(s); Bud stage with detached bracts
Photographer:Steve Dewey, Utah State University
 Additional Resolutions and Image Usage
 
Number:0022038
Description: Plant(s);
Photographer:Norman E. Rees, USDA Agricultural Research Service
 Additional Resolutions and Image Usage
 
Number:0022037
Description: Plant(s);
Photographer:Norman E. Rees, USDA Agricultural Research Service
 Additional Resolutions and Image Usage
 
Number:1459262
Description: Plant(s);
Photographer:Steve Dewey, Utah State University
 Additional Resolutions and Image Usage
 
Number:0022039
Description: Infestation;
Photographer:Norman E. Rees, USDA Agricultural Research Service
 Additional Resolutions and Image Usage
 
Number:5306049
Description: Fruit(s);
Photographer:Steve Hurst, USDA NRCS PLANTS Database
 Additional Resolutions and Image Usage
 

External Links

Invasive Reference(s)

Subject Reference(s)

  • USDA, NRCS. 2001. The PLANTS Database, Version 3.1, National Plant Data Center, Baton Rouge, LA 70874-4490 USA. - http://plants.usda.gov/