St. John's Wort

Hypericum perforatum 'Topas' Clusiaceae

Growth habit



Long-lived perennial


Robison Herb Garden

Source of plant

Fedco Seeds


Typically grows from a woody, branched rootstock to 1-3™ tall, and features a showy display of star-shaped, yellow flowers (1 1/2 diameter) that bloom in pyramidal compound cymes in summer (June-August). Each flower has 5 yellow petals peppered with black dots, a pistil with 3 styles and a center boss of bushy yellow stamens. Stem-clasping, elliptic to oblong leaves to (1 1/4 long) have translucent dots and black marginal punctations. Foliage has an unpleasant aroma when bruised or rubbed.Since ancient times, hypericum plants have been used as herbal treatments for a variety of medical problems including externally for wounds, inflammations, burns, skin disorders, and nerve pain and internally for anxiety, depression and insomnia. The flowers were at one point gathered and displayed to ward off evil spirits. Flowers are typically in bloom on the birthday of St. John the Baptist (June 24). Wort is a name often given to a healing plant. The active ingredient in the leaves and flowers is hypercin.Additional common names include goatweed or Klamath weed (plant was first discovered growing in the wild in California near the Klamath River).'Topas' is very similar to the species, except it is noted for containing a higher percentage of hypercin.

USDA Hardiness Zone


Special characteristics

medicinal/pharmaceutical, other ethnobotanical uses