[Cal-IPC] Invasiveness: 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. (link added by Mary Ann Machi)

[Wikipedia] Endemic to the Canary Islands and Madeira. Noxious weed status: Hypericum canariense is a species of flowering plant in the family Hypericaceae known by the common name Canary Islands St. John's wort. It is the sole member of Hypericum sect. Webbia. It is endemic to the Canary Islands and Madeira, where it grows in low-moisture scrub and forested slopes of the five westernmost islands from 150 to 800m. It is also known as an introduced species in Australia, New Zealand, and the US states of California and Hawaii, where it is an escaped ornamental plant and generally considered a minor noxious weed. (link added by Mary Ann Machi)