Hortus Botanicus Leiden, Netherlands

Common name: Sint-Janskruid, Perforate St John's wort

Family: Hypericaceae (Hertshooifamilie)

Distribution: Europa (de soort)

Hardiness: Zone 03

Life form: Perennial

Comments: Medieval Plants Tour - St John’s wort is named after John the Baptist, because it flowers on 24 June, which is the feast of St John. In the Middle Ages, people were intrigued by the red juice that could be pressed from the flower buds. Some thought that it was the blood of John the Baptist, who was beheaded. Others claimed that this herb grew under the crucifix to which Christ was nailed; the plant had caught drops of blood and these had turned it red. In the Middle Ages St John’s wort was known as ‘king’s crown’ because of the golden yellow flowers. The plant’s leaves are studded with little oil glands, which look like holes, so it is also known as herba perforata (‘perforated plant’) in Latin and ‘hondertgatichgewas’ (‘plant with a hundred holes’) in Dutch. The devil was supposed to have made these holes with a needle, in the hope of weakening the miracle plant. All in vain, because St John’s wort can keep demons at bay and strengthens the heart.