California Invasive Plant Council

Hypericum canariense

Synonyms: Hypericum floribundum

Common names: Canary Island St. Johnswort; Grenadillo

Hypericum canariense (Canary Island hypericum) is a rhizomatous perennial shrub (family Clusiaceae) found on the central and south coast of California and in the southern San Francisco Bay region. Canary Island hypericum infests disturbed areas, especially in coastal sage scrub and grassland habitats. This ornamental shrub forms dense stands that exclude native species. It is not yet widespread, but its prolific seed production makes rapid spread possible.

Cal-IPC Rating: Moderate — Alert

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.

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

• Weed biological control agents approved for California. Pitcairn, Michael J.; Smith, Lincoln; Moran, Patrick. Vol 22, Issue 1
• Wildland Weed News. editor. Vol 17, Issue 2
• Hypericum canariense. Tu, Mandy. Vol 10, Issue 4
• Red alert! Hypericum canariense L. (Canary Island St. Johnswort). Tu, Mandy. Vol 09, Issue 3

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.

• Successes, failures, and lessons from the Orange County CNPS Emergent Invasive Program. Vanderhoff, Ron (2019)

Other Hypericum canariense 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.
• Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.