Hypericum perforatum, known as St John’s-wort, common Saint John’s wort and St John’s wort, is a flowering plant in the family Hypericaceae. The common name “St John’s wort” may be used to refer to any species of the genus Hypericum. Therefore, Hypericum perforatum is sometimes called “common St John’s wort” or “perforate St John’s wort” in order to differentiate.
Hypericum perforatum is native to parts of Europe and Asia but has spread to temperate regions worldwide as a cosmopolitan invasive weed.
The common name “St John’s wort” comes from its traditional flowering and harvesting on St John’s Day, 24 June.