About Hypericum grandifolium Choisy
Hypericum grandifolium Choisy is a bushy shrub that reaches 50 to 180 centimeters in height. Its branches typically grow upright or nearly upright. Across its entire native range, different populations of the species are nearly identical in appearance, with very little geographic variation in physical traits. The native distribution of Hypericum grandifolium is limited to the Spanish Canary Islands and the Portuguese island of Madeira. It is grown as a garden plant, and has become invasive after escaping from cultivation in non-native regions. For example, it is invasive and actively spreading in the San Francisco Bay Area, where it forms dense stands that outcompete native plants. It was first recorded in California in 2010, and the California Invasive Plant Council has identified it as a potential threat to native local ecology. Hypericum grandifolium has become naturalized in parts of Australia and Chile, and is classified as a weed in other areas of Australia, including South Australia and Victoria. On the Canary Islands, it occurs at elevations between 200 and 1,500 meters, while on Madeira it grows at 400 to 500 meters elevation. Its natural habitat is within evergreen forests, including forests dominated by Laurus trees. It can also be found on stony hillsides and cliffsides. In areas cleared of forest by wildfire, Hypericum grandifolium acts as a colonizing species, growing in the years after this disturbance. In California, where it is non-native and invasive, it often grows alongside the also invasive shrub Ageratina adenophora. Hypericum grandifolium serves as a host for several parasites. These include the wasp Euderomphale gomer, the rust fungus Melampsora hypericorum, and rarely the honey fungus Armillaria. Hypericum grandifolium can reproduce via its rhizomes, and can also form thickets from its rootstock. It can be propagated from either softwood or semi-ripe cuttings.
