Knapweeds (Diffuse & Spotted & Russian)
Centaurea diffusa & Centaurea stoebe & Rhaponticum repens
- 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.
- Hand pulling; herbicide control early in the growing season while still green; biological control agents; trained livestock grazing.
- Saskatchewan Invasive Plant Species Guide
Identification Guide for Alberta Invasive Plants
Weeds of the Prairies
WeedsBMP App BC – iOS | Android
Photos
Centaurea diffusa & Centaurea stoebe & Rhaponticum repens
- 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.
- Hand pulling; herbicide control early in the growing season while still green; biological control agents; trained livestock grazing.
- Saskatchewan Invasive Plant Species Guide
Identification Guide for Alberta Invasive Plants
Weeds of the Prairies
WeedsBMP App BC – iOS | Android