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.

Cal-IPC Rating: Moderate

Cal-IPC Assessment

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.

Weed RIC 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

  • 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.

Other Ageratina adenophora Information

  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - See the distribution of this species on Calflora's map of California.
  • CalWeedMapper - Distribution information with ability to determine regional priorities.
  • Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • USDA PLANTS Database - Federal database with information on identification and distribution, and links to websites in individual states.