Centaurea stoebe L. ssp. micranthos (Gulger) Hayek
Centaurea maculosa auct. non Lam.
Centaurea biebersteinii DC
Acosta maculosa auct. non Holub
- Moss, Flora of Alberta – Rare
- Global Invasive Species Database – Yes
- NatureServe Rank – High
- Haber, Upland – Minor
- Haber, Wetland – No
- CWF, Status & Invasive Range – Potential, BC, SK, AB, MB, ON, QC, NF & Northern NWT, Yukon
- Alberta Revegetation Guidelines – No
- The Nature Conservancy – Yes, w/ ESA
- CBCN – Potential
- AB Weed – Prohibited noxious
Rare, ISSG for most of Canada, AB included. In sagebrush steppe (Artemisia tridentata), post-fire soil water increases favour Knapweed which once established is able to draw moisture from greater depths and permanently reduce soil moisture below levels normal prior to infestation.
[]Link to Global Invasive Species Database "Centaurea biebersteinii is a biennial or short-lived perennial composite and a very aggressive invader. It has been reported to grow on a wide variety of habitats, especially industrial land..."
 Link to Bugwood Invasipedia for extensive information on biology, ecology, and management of this species.
Roché C.T., and B.F. Roché Jr. 2000. Identification of Knapweeds and Starthistles in the Pacific Northwest: PNW432. Pacific Northwest Extension Publication. 22 pp. 
Alberta Invasive Plant Council factsheet: https://www.invasiveplants.ab.ca/Downloads/FS-SpottedKnapweed.pdf