Centaurea calcitrapa

Centaurea calcitrapa_purple starthistle_flowering head_JM DiTomaso
Photo: Joseph DiTomaso

Common names: purple starthistle

Centaurea calcitrapa (purple starthistle) grows as an annual, biennial or perennial (family Asteraceae) in fields, roadsides, disturbed open sites, grasslands, overgrazed rangelands, and logged areas in the northern and central coast ranges of California. Centaurea species may produce allelopathic effects and are highly competitive with other plants, often displacing desired vegetation.

Cal-IPC Rating: Moderate?

CDFA Rating: -*?


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.

Species ID Card

Invasive Species ID Card - To support field identification of early detection species, Cal-IPC has designed a set of Species ID cards that can be downloaded, printed double-sided, and trimmed to size.

Weed Management Notes

  • Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

Cal-IPC Symposium Presentations

Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.

Other Centaurea calcitrapa Information

  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - Distribution map and records of this species in California.
  • CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
  • EDDMapS - Distribution of this species in North America.
  • Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.
  • Additional photos

    Centaurea calcitrapa_flowerhead_copyright_2015_NealKramer
    Centaurea calcitrapa (purple starthistle) flowerhead. Photo: &#169 2015 Neal Kramer
    Centaurea calcitrapa_infestation_copyright_2008_NealKramer
    Centaurea calcitrapa (purple starthistle) infestation. Photo: &#169 2008 Neal Kramer
    Centaurea calcitrapa_rosette_copyright_2008_NealKramer
    Centaurea calcitrapa (purple starthistle) rosette. Photo: &#169 2008 Neal Kramer