Family: Hypericaceae (St John's Wort Family).
Native of Europe.
Occurrence: St Johnís Wort is a widespread weed, particularly in granite areas. It is common along roadsides and paddocks and is a major weed on Mt Alexander.
St Johnís Wort is poisonous to stock and is a proclaimed noxious weed (listed as Regionally Controlled in central Victoria).
It is usually lives for two years. Take care if pulling by hand, as contact with the plant may cause a rash. The main dispersal method is by seed. A well-established plant can produce 30,000 seeds per year, which can remain dormant for several years. The plant may also spread by cultivation, when the underground stems are chopped up by machinery.
St Johnís Wort is associated with St John the Baptist and is reputed to have magical powers e.g. plants hung in a house deter witches and death from entering. Despite being a poisonous plant, it is sometimes used medicinally.
Similar native species: Small St Johnís Wort and Matted St Johnís Wort both grow in Central Victoria. They are much smaller plants and the leaves are without oil-dots.