Ageratina adenophora (croftonweed, euphatorium)

Ageratina adenophora

Photo Joseph DiTomaso

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 Inventory rating: Moderate

Cal-IPC Resources on Ageratina adenophora

• California Invasive Plant Inventory Assessment Form (pdf) - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
• Cal-IPC News - Articles from our quarterly newsletter. Each issue is available as a pdf. List of articles on Ageratina adenophora.
• Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium. List of articles on Ageratina adenophora.
• Don't Plant a Pest! - Select your region to find non-invasive alternatives to ornamental species. Also see our statewide brochure on trees.

Cal-IPC News Articles

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

Cal-IPC Symposium Proceedings

• 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 Resources on Ageratina adenophora

• 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.
• The Nature Conservancy Management Summary - Information compiled by TNC land managers. Photos included for some species.
• 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.

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