St. John’s Wort

(Hypericum perforatum)

St. John’s Wort (Hypericum perforatum)

Michael H. Lemmer

CC BY-SA 2.5

Image By: Michael H. Lemmer

Recorded By:

Estimated Native Range

Summary

Hypericum perforatum, commonly known as St. John’s Wort, is a deciduous perennial herb native to open woodlands, grasslands, and meadows across Eurasia. It is well-adapted to a range of disturbed sites, including roadsides and pastures. The plant typically grows up to 1 meter (3 feet 3 inches) high, with reddish, erect, and branched stems that become woody near the base. The leaves are narrow, oblong, yellow-green, and feature distinctive translucent dots, which are actually glandular tissue. From late spring to early to mid-summer, St. John’s Wort produces showy, bright yellow flowers with five petals and sepals, each adorned with conspicuous black dots. The flowers are arranged in broad helicoid cymes at the ends of the upper branches.

St. John’s Wort is valued for its medicinal properties, particularly in treating depression, and its use in traditional medicine dates back to ancient times. It is also appreciated for its ornamental qualities, with its vibrant yellow flowers adding color to gardens. This herb is often used in naturalistic plantings, meadow gardens, and as ground cover. It thrives in full sun to part shade and is adaptable to various soil types, including sandy soils, provided they have adequate drainage. While it has medium water requirements, it can tolerate drought once established. Gardeners should be aware that Hypericum perforatum can be invasive outside its native range, and it may outcompete native vegetation.CC BY-SA 4.0

Plant Description

Plant Type: Herb
Height: 1-3 feet
Width: 0.8-2 feet
Growth Rate: Moderate
Flower Color: Yellow
Flowering Season: Summer
Leaf Retention: Deciduous

Growth Requirements

Sun: Full Sun, Part Shade
Water: Medium
Drainage: Fast, Medium, Slow

Common Uses

Bank Stabilization, Bee Garden, Bird Garden, Butterfly Garden, Deer Resistant, Drought Tolerant, Erosion Control, Fragrant, Low Maintenance, Showy Flowers

Natural Habitat

Open woodlands, grasslands, meadows, and disturbed sites such as roadsides and pastures

Other Names

Common Names: Klamath Weed , Klamathweed , St. Johnswort , Common St. John’s Wort , Perforate St. John’s-Wort , Goatweed , St. John’s-Wort , Tiptonweed , Racecourseweed , Johanneskruid

Scientific Names: Hypericum perforatum , Hypericum vulgare , Hypericum perforatum subsp. vulgare , Hypericum perforatum var. elatum , Hypericum assurgens , Hypericum perforatum f. brevispathum , Hypericum perforatum f. lucidum , Hypericum perforatum var. alpinum , Hypericum perforatum var. anomalum , Hypericum perforatum var. ellipticum

GBIF Accepted Name: Hypericum perforatum L.