Exotics Plant Species Report
Yellow star thistle (Centaurea solstitialis)
October 2000

Please keep a lookout for Yellow star thistle (Centaurea solstitialis) in San Diego. Tocalote (Centaurea melitensis), a close look-alike to Yellow star thistle, is fairly widespread in the county. The true Yellow star thistle has had a somewhat limited distribution in the county to date although it has had devastating consequences elsewhere in the west. Yellow star thistle has long spines on the head (10-25 mm versus 10-15 mm for Tocalote) and is a taller more robust plant than Tocalote. The plant is currently spreading rapidly along SR-52 in the Mission Trails area. Please call Bill Winans at County Agriculture or Cindy Burrascano at (619) 421-5767 to report occurences.

-- Cindy Burrascano

More information and photos of Yellow Star Thistle can be found at:
Wildland Weeds Management & Research Program, The Nature Conservancy
UC Pest Management Guidelines, University of California Statewide Integrated Pest Management Project:

Other Resources:
CNPS Invasive Exotics (state site)
CNPS Policy on Invasive Exotics
California Exotic Pest Plant Council