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. It is native to southern and central Mexico.

Cal-IPC Rating: Moderate?

CDFA Rating: B?


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.

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 Ageratina adenophora Information

  • 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

    Ageratina adenophora_growth habit_copyright_ 2019_NealKramer
    Ageratina adenophora (eupatory) growth habit. Photo: &#169 2019 Neal Kramer
    Ageratina adenophora_inflorescence_copyright_2009_NealKramer
    Ageratina adenophora (eupatory) inflorescence. Photo: &#169 2009 Neal Kramer
    Ageratina adenophora_leaves_copyright_2011_NealKramer
    Ageratina adenophora (eupatory) leaves. Photo: &#169 2011 Neal Kramer