Hypericaceae

Hypericum perforatum

Common Names: St. John’s wort

Plant Form: Perennial woody to fleshy herb. Size: Usually 30-70 cm tall but can reach 1.2 m. Stem: Flowering stems upright and woody, non-flowering stems form tangled thickets Leaves: Opposite pairs on stem, spotted with oil glands clearly visible when held up to light. Flowers: Star shaped 1-2 cm diameter, bright yellow with 5 petals, Fruit and Seeds: Sticky 3 cell capsules with numerous tiny golden-brown seeds. Habitat: Roadsides, farmland, grasslands, riverbanks, railways. Distinguishing Features: Distinct from other common species. Native St John’s wort (Hypericum species) are smaller and with more orange flowers. Impacts: Can cause weight loss or even death in grazing animals, especially horses, can cause skin irritation in humans, increases fire risk.

Flowers are golden yellow

Seedpods are brown

Infested areas are light brown

Overwinters as a prostrate herb