St. John's Wort (Hypericum perforatum): Famous Medicinal Herb with Perforated Leaves

Overview

St. John's wort (Hypericum perforatum) is a perennial herb native to Europe, now naturalized worldwide. It grows 1-3 feet tall with opposite, oblong leaves that appear perforated (translucent dots) when held to light. Bright yellow, five-petaled flowers with prominent stamens bloom in early to mid-summer. The black dots on petals and leaves contain hypericin.

Botanical Details

• Family: Hypericaceae (formerly Clusiaceae)
• Genus: Hypericum
• Species: perforatum

Uses & Cautions

Widely studied for mild to moderate depression; also used topically for wounds, burns, nerve pain. Interacts with many medications (antidepressants, birth control, anticoagulants)—consult a healthcare provider. Can cause photosensitivity. Invasive in some regions; check local status. Grows in full sun, well-drained soil; tolerates drought.