They are evergreen with triangular leaves. Divide mature plants every 3 or 4 years. Good for use in borders and rock gardens. Some flowers have red centers. Plants benefit from winter mulching in zones 5-7.
Flower petals have black dots on their margins.
Flowers are said to begin blooming June 24, St. John's Day. Full sun to light shade. Not choosy about soil conditions. Plants can become weedy where grasses are not thick and may be difficult to eradicate. St. John's Wort is on the noxious weed list for several states in the West.