Carduus tenuiflorus

Photo courtesy Joseph DiTomaso

Common names: slenderflower thistle; Italian thistle; multiheaded thistle; seaside thistle; shore thistle; winged plumeless thistle

Carduus tenuiflorus (slender flowered thistle) is a tall annual or biennial (family Asteraceae) located along the California coast and in the Central Valley and Sierra foothill grasslands. It is similar in appearance and habitat to Italian thistle (Carduus pycnocephalus), but is less widely distributed.

Rating: Limited

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.
  • CalWeedMapper - Statewide maps, climate models, and reports.
  • 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

    • USDA PLANTS database -
      Federal database with information on identification and distribution, and links to websites in individual states.
    • Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from the UC Berkeley Jepson Herbarium.
    • CalFlora - Distribution information by county based on submitted observations and herbarium specimens.
    • CalPhotos - Images of plants taken mostly in California.
    • Natural Resource Projects Inventory - State database with information on resource management projects throughout California. Query by the species of interest.

    Symposium Presentations

    • None for this species

    Cal-IPC News Articles

    • Pitcairn, M. (2000). All weeds that have approved biological control agents, accidental introductions and others. CalEPPC News. 8.