Diffuse KnapweedCentaurea diffusa Lam.
- Moss, Flora of Alberta – Rare
- Global Invasive Species Database – Yes
- NatureServe Rank – High
- Haber, Upland – No
- 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 – No
- AB Weed – Prohibited Noxious
Rare, a pioneer species that can quickly invade disturbed and undisturbed grassland, shrubland, and riparian communities. Once established, it outcompetes and reduces the abundance of desirable native species. It contains the allelopathic chemical cnicin, which can suppress the growth of other species. It is usually described as a biennial, but actually often lives longer---although it does die after flowering and producing seed.
 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.