Centaurea diffusa & Centaurea stoebe & Rhaponticum repens

1. Biennial (diffuse) or perennial (spotted & Russian) with long tap root; deeply lobed leaves; contain allelopathic chemicals that supress growth of other plants; spotted knapweed has pink to purple-coloured flowers while diffuse has white flowers; Russian knapweed has white to pink flowers with membranous bracts.
2. Hand pulling; herbicide control early in the growing season while still green; biological control agents; trained livestock grazing.
3. Saskatchewan Invasive Plant Species Guide
   Identification Guide for Alberta Invasive Plants
   Weeds of the Prairies
   WeedsBMP App BC – iOS | Android

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