Mêl Cilgwenyn Premium Wildflower Seeds

Perforate St John’s Wort

Hypericum perforatum

Best Time to See: June, July, August, September

Habitat: Grassland, woodland, heathland, coast

Colour: Purple, Pink

The subject of much myth and legend, and a herbal remedy, Perforate St John's-wort is a familiar flower.

Its bright yellow flowers appear from June to September and the blood-red juice that exudes from its stems has made it a focus for much myth and ritual. For instance, torchlight processions and gorse-burning were just some of the activities undertaken on Midsummer's Day, a pagan festival soon replaced by the Feast of St John the Baptist, hence the common name of this plant. It's also said that the red juice from its stem represents his bloody murder.


Perforate St John's-wort can easily be identified as it appears to have many tiny 'holes' in its leaves; these are actually colourless glands that give off a 'foxy' smell. It has bright yellow, star-shaped flowers that are peppered with tiny black dots.

Habitat and distribution

Perforate st John's-wort can be found in open woods, along hedgerows and roadside verges, and on waste ground. Perforate St John’s Wort can be found in grassland, woodland, heathland and moorland, on farmland and on the coast. Found throughout the UK, but particularly widespread in England and Wales.

Did you know?
  • St Johns Wort is known as an invasive species in more than 20 countries, including South and North America, India, New Zealand, Australia and South Africa.
  • Ingestion by livestock such as horses, sheep, and cattle can cause photosensitization, central nervous system depression, spontaneous abortion, or death.
  • In western North America the beetles Chrysolina quadrigemina, C. hyperici, and Agrilus hyperici have been introduced as biocontrol agents.
  • Common St John's wort has been used in herbalism for centuries. It was thought to have medical properties in classical antiquity and was a standard component of theriacs, from the Mithridate of Aulus Cornelius Celsus' De Medicina (ca. 30 CE) to the Venice treacle of d'Amsterdammer Apotheek in 1686. Folk usages included oily extract (St John's oil) and Hypericum snaps. Hypericum perforatum is a common species and is grown commercially for use in herbalism and traditional medicine.
  • The red, oily extract of H. perforatum has been used in the treatment of wounds, including by the Knights Hospitaller, the Order of St John. Both hypericin and hyperforin are under study for their potential antibiotic properties.
Conservation status

Common throughout the British Isles, but has declined slightly at the western edge of its range.