Photo Credit: Alexander Mrkvicka, Botanik im Bild, retrieved from http://flora.nhm-wien.ac.at, modified from the original
Common Name: Tyrol Knapweed Scientific Name: Centaurea nigrescens Habitat: roadsides, disturbed areas, grassland, forests - open areas 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. |
Origin
Tyrol knapweed is a perennial native to western Asia and south-western Europe.
Legislated Because
Tyrol knapweed can invade open forests, grasslands, and prairies. It can out-compete native vegetation, reduce biodiversity and forage species.
Description
The flowers of Tyrol knapweed are 20-30 mm wide and have peripheral petals that are distinctively larger than its inner petals. The bracts have hair-like margins. The 'hairs' are shorter than the triangular centre of the bract allowing the lower green part of the bracts to be visible.
Most leaves are lance-shaped or elliptic. A few leaves on each plant might have one or two lobes. The leaves and the stem have stiff hairs.
Tyrol knapweed grows up to 150 cm tall.
Learn more about this species:
See Fact Sheet - Alberta Invasive Species Council