Russian Knapweed (Rhaponticum repens)

 
 
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Description
A perennial that can grow to 1 m in height, with creeping roots. Stems originate from a basal rosette of leaves. The rosette leaves can be unlobed to very lobed and are 5-10 cm long. Stem leaves are oblong, pinnately lobed to entire and up to 15 cm in length at the base of the stem and become smaller and less lobed toward the top. Russian knapweed produces flowers that are pink to purple and turn straw colored as they mature. The flower heads are approximately 0.5 cm in diameter and urn shaped.

Key Identifiers
  • Slivery-green, hairy, lower leaves long and lobed, upper leaves smaller & toothed
  • Bract is pearly and papery, with no noticeable fringes or spines
  • Creeping roots
Location in Canada
BC, Manitoba, Ontario, Sask. and Alberta all report the presence of Russian Knapweed.

Resources
Pacific Northwest Extension Publication - Identification of Knapweed and Starthistles in the Pacific Northwest

Similar species
(Centaurea spp.) Other knapweeds are going to be similar to Russian knapweed. The key feature for differentiating all knapweeds from one another is to compare the unique bracts. The link under “Resources” is an excellent resource to walk you through identifying knapweeds.

Steve Dewey, Utah State University, Bugwood.org

Steve Dewey, Utah State University, Bugwood.org

Steve Dewey, Utah State University, Bugwood.org
May be mistaken for a thistle at a passing glance but upon inspection, all parts of Russian knapweed lack spines.
 
 
 
 

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For more information about the content of this document, contact Nicole Kimmel.
This document is maintained by Shelley Barkley.
This information published to the web on April 2, 2012.
Last Reviewed/Revised on March 21, 2014.