St John's Wort has been in cultivation since around 1600. Native to Britain, Europe and North Africa, the common name is a corruption of toute-saine meaning 'heal all', reflecting the supposed myriad of medicinal uses it once had.
Surrounded by mythology it has been clearly valued culturally since ancient Greece, when Hypericum performatum in particular was considered to provide protection from devils and evil spirits. Since then it has also been linked with light and rebirth and until fairly recently these beliefs led in many parts of Europe to its use in the rituals associated with the feast of St John, Christmas and the summer solstice.
During the Middle Ages it was also even thought to act as a fertility aid for barren women.