Ageratina adenophora

Ageratina adenophora_Croftonweed_JM DiTomaso
Photo Joseph DiTomaso

Synonyms: Eupatorium adenophorum, E. glandulosum, E. pasadense.

Common names: eupatory, croftonweed, thoroughwort, sticky snakeroot, catweed, hemp agrimony, sticky agrimony, sticky eupatorium

Ageratina adenophora (croftonweed, eupatorium) is a perennial herb or small shrub (family Asteraceae) found along the coast of California and in the South Coast and Transverse Ranges. It prefers disturbed areas, coastal canyons, riparian areas and scrub, and is especially invasive in mild coastal areas. Originally introduced to California as an ornamental plant, croftonweed escaped cultivation by producing abundant seed that is dispersed via wind, water, soil movement, and by clinging to animals and people. This invasive plant is considered noxious in parts of Asia, Australia, New Zealand and Hawaii.

Rating: Moderate

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

Symposium Presentations

  • Bomkamp, T. (1993). The distribution and impacts of escaped exotic Ageratina adenophora in Callifornia: A preliminary assessment. California Exotic Pest
    Plant Symposium '93. Westlake Village, CA.

Cal-IPC News Articles

  • (1993). California Exotic Pest Plant Council draft list exotic plants of greatest concern October 1993. CalEPPC News. 1: 6.