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Bighead knapweed
Photo credit: Daniel Laubhann

Common Name: Bighead knapweed

Scientific Name: Centaurea macrocephala

Habitat: ornamental beds, farmland, grassland

Provincial Designation: Prohibited Noxious

Prohibited Noxious weeds are plant species that are designated as "prohibited noxious" in the Alberta weed regulation. Prohibited noxious weeds must be destroyed, meaning all growing parts need to be killed or the plant's reproductive mechanisms need to be rendered non-viable.


Bighead knapweed is native to Eastern Europe and was introduced to North America as an ornamental garden plant. Its earliest confirmed sighting in North America was recorded in 1812.

Legislated Because

It out-competes grasses and other forage species, reducing food sources for wildlife and livestock.


Bighead knapweed has conspicuously large, yellow flowers that are 3-8 cm wide.

The leaves are elliptic and alternately arranged. The leaves grow pointing upwards and blades of the leaves extend down along the stem creating characteristic vertical “wings” on the stem.

This knapweed grows up to 150 cm tall.

Learn more about this species:

SeeFact Sheets - Alberta Invasive Species Council

For More Information

Weed Management


In Edmonton: 311

Outside Edmonton: 780-442-5311


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