Centaurea stoebe ssp. micranthos

Photo courtesy Bob Case

Synonyms: Centaurea maculosa; Centaurea biebersteinii, Centaurea stoebe ssp. stoebe and ssp. maculosa

Common names: spotted knapweed

Centaurea maculosa (spotted knapweed) is a biennial to short-lived perennial (family Asteraceae). It can be found in disturbed open sites, grasslands, overgrazed rangelands, roadsides and logged areas. It crowds out native species and forage for livestock, and can invade undisturbed native bunchgrass stands. An individual plant may produce as many as 40,000 seeds.

Jepson Manual, 2nd Edition: Centaurea stoebe subsp. micranthos

Rating: High

Cal-IPC Resources

  • Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
  • Cal-IPC News - Our quarterly newsletter. Each issue is available as a pdf.
  • Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium.
  • Don't Plant a Pest! - Select your region to find non-invasive alternatives to ornamental species. Also see our statewide brochure on trees.

    Other Resources

    Symposium Presentations

    • Smith, R. L., V. F. Carrithers, et al. (2006). Managing rangeland invasive plants with Aminopyralid (MilestoneTM). Cal-IPC Symposium. Rohnert Park, CA.
    • Carrithers, V., B. Miller, et al. (2005). Aminopyralid: A new reduced risk active ingredient for control of broadleaf invasive and noxious weeds. California Invasive Plant Council Symposium 2005. Chico, CA.
    • Goodwin, K. (2005). Montana weed prevention areas: Partnerships for rangeland protection. California Invasive Plant Council Symposium 2005. Chico, CA.
    • Melbourne, B., A. Hollander, et al. (2004). Integrating ecological, social, and economic perspectives on the spread of invasive species. California Invasive Plant Council Symposium 2004. Ventura, CA.
    • Brucker, P. (2003). Salmon River cooperative noxious weed program for 2003. California Invasive Plant Council Symposium 2003. Kings Beach, CA.
    • Donaldson, S., W. West, et al. (2003). Getting the job done: Working within the regulatory environment at Lake Tahoe to manage weeds. California Invasive Plant Council Symposium 2003. Kings Beach, California, CA.
    • Norgaard, K. M. (2003). Community responses to spotted knapweed: A sociological view. California Invasive Plant Council Symposium 2003. Kings Beach, CA.
    • Tu, M. and J. M. Randall (2003). 2003 Cal-IPC red alert! New invasions, recent expansions, and a few others to be on the look-out For. California Invasive Plant Council Symposium 2003. Kings Beach, CA.
    • Brucker, P. (2002). Salmon River cooperative noxious weed program. California Exotic Pest Plant Council Symposium 2002. Sacramento, CA.
    • Leavitt, J. R. and C. Pirosko (2002). A brief overview of the California Dept. of Food and Agriculture’s A-rated noxious weed education and eradication program. California Exotic Pest Plant Council Symposium 2002. Sacramento, CA.
    • S. R. R. (2002). Determining the effectiveness of eradicating Centaurea maculosa from the Salmon River wildland ecosystem. California Exotic Pest Plant Council Symposium 2002. Sacramento, CA.
    • Tu, M. and J. M. Randall (2002). 2002 Red alert! New introductions and recent expansions in California. California Exotic Pest Plant Council Symposium 2002. Sacramento, CA.
    • Marler, M. J. and R. M. Callaway (2000). Role of mycorrhizae in Centaurea invasions. California Exotic Pest Plant Council Symposium 2000. Concord, California, CA.
    • Young, J. A. and C. D. Clements (2000). Purple starthistle seed germination. California Exotic Pest Plant Council Symposium 2000. Concord, California, CA.
    • Young, J. A., C. D. Clements, et al. (2000). Purple starthistle seed germination. California Exotic Pest Plant Council Symposium 2000. M. Kelly. Ontario, CA.
    • O'Connell, R. A. (1999). The state of California's noxious weed eradication programs. California Exotic Pest Plant Council. Sacramento, CA.
    • Butler, E. and S. Britting (1998). Mapping and control of weeds in the American River Parkway. California Exotic Pest Plant Council Symposium '98. Ontario, CA.
    • DiTomaso, J. M., C. Benefield, et al. (1998). Reproductive biology of yellow starthistle (Centaurea solstitialis) maximizing late season control. California Exotic Pest Plant Council Symposium '98. Ontario, CA.
    • DiTomaso, J. M., G. B. Kyser, et al. (1998). Prescribed burning for control of yellow starthistle (Centaurea solstitialis) and enhanced native plant diversity. California Exotic Pest Plant Council Symposium '98. Ontario, CA.
    • Kelly, M. (1998). SWAT: Special weed action teams as abassadors for education and energy. California Exotic Pest Plant Council '98 Symposium. Ontario, CA.
    • Gerlach, J. D. (1997). How the west was lost: Reconstructing the invasion dynamics of yellow star-thistle and other plant invaders of western rangelands and natural areas. California Exotic Pest Plant Council Symposium '97. Concord, CA.
    • O'Connell, R. A. (1997). Hydrilla: A case study: The state of California's noxious weed eradication programs. California Exotic Pest Plant Council Symposium '97. Concord, CA.
    • Thomsen, C. D., W. A. Williams, et al. (1996). Yellow starthistle management with grazing, mowing, and competitive plantings. California Exotic Pest Plant Council Symposium '96. San Diego, CA.
    • DiTomaso, J. M. (1995). Overview of extension non-crop weed research in California. California Exotic Pest Plant Council Symposium '95. J. Lovich, J. Randall and M. Kelly. Pacific Grove, CA.
    • Rusmore, J. T. (1995). Use of fire and cutting to control yellow starthistle. California Exotic Pest Plant Council Symposium '95. M. Kelly and J. Lovich. Pacific Grove, CA.
    • Westbrooks, R. G. (1995). Federal regulatory efforts to minimize the introduction and impacts of exotic pest plants in the United States. CalEPPC Symposium '95. Asilomar, CA.
    • Pitcairn, M. (1993). Introduction and distribution of biological control agents against exotic weeds in California. California Exotic Pest Plant Symposium '93. Westlake Village, CA.

    Cal-IPC News Articles

    • Brusati, E., D. Morawitz, et al. (2011). Prioritizing Regional Response to Invasive Plants in the Sierra Nevada. Cal-IPC News. 19: 4, 5, 10.
    • O'Rourke, B. and J. Horenstein (2009). Tackling invasive plants on California Sept. of Fish & Game lands. Cal-IPC News. 17: 12.
    • Donaldson, S. (2003). Fighting weeds in the Tahoe basin. CalEPPC News. 11: 7.
    • Pitcairn, M. (2000). All weeds that have approved biological control agents, accidental introductions and others. CalEPPC News. 8.