Centaurea solstitialis

Centaurea solstitialis_yellow starthistle_flowerhead_JM DiTomaso
Photo: Bob Case

Common names: yellow starthistle

Centaurea solstitialis (yellow starthistle) is a bushy winter annual (family Asteraceae) from the Mediterranean region in Europe that has invaded over 12 million acres in California. Yellow starthistle inhabits open hills, grasslands, open woodlands, fields, roadsides, and rangelands, and it is considered one of the most serious rangeland weeds in the state. It propagates rapidly by seed, and a large plant can produce nearly 75,000 seeds. Plants are gray-green in color and produce yellow flower heads armed with stiff, long spines in late June and July. Several insects from the Mediterranean region, including weevils and flies, have been employed as biocontrol agents for yellow starthistle with minor success.

Cal-IPC Rating: High?

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.

Special Reports

  • Yellow Starthistle Management Guide - Provides a comprehensive overview of treatment methods for yellow starthistle, including each method's advantages and disadvantages, timing, and best fit in a strategic management plan.
  • Pest Notes on Yellow Starthistle - from the University of California's Statewide Integrated Pest Management Program

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 solstitialis Information

  • Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.
  • 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 solstitialis_yellow starthistle_ Bob Case_cropped
    Centaurea solstitialis (yellow starthistle) seedlings. Photo: Bob Case
    Centaurea solstitialis (yellow starthistle) flower head development stages. Photo: Ron Vanderhoff
    Centaurea solstitialis_infestation_copyright_2008_NealKramer
    Centaurea solstitialis (yellow starthistle) infestation. Photo: &#169 2008 Neal Kramer
    Centaurea solstitialis_leaves, stems, flower heads_copyright_2014_NealKramer
    Centaurea solstitialis (yellow starthistle) leaves, stems, flower heads. Photo: &#169 2014 Neal Kramer