Hypericum perforatum L.
Common St. John's Wort, St. John's Wort, Goatweed, Klamath Weed, Klamathweed, Perforate St. John's Wort, Racecourseweed, Tipton's Weed, Tiptonweed, Rosin Rose, Chase-Devil
Hypericum assurgens, Hypericum deidesheimense, Hypericum lineolatum, Hypericum marylandicum
Bloom Time: Between late spring and early to mid-summer
Hypericum perforatum has erect stems that can grow up to 100 inches (2.5 m) of height. Leaves are small, the size of up to 1.6 inches (4 cm), egg-shaped, opposite and stemless, full of small and translucent dots or glands filled with essential oils. The flowers appear in broad cymes at the ends of the upper branches, between late spring and early to mid-summer.
How to Grow and Care
If you live in USDA plant hardiness zones 5 or 6 to 10 and have a partially shaded site, you can probably grow St. John's Wort. The plant isn't particular about the soil type. It grows well in sand, clay, rocky soil or loam, and tolerates acidic to slightly alkaline pH.
St. John's Wort adapts to both moist and dry soil, and even tolerates occasional flooding. It also withstands drought but grows best with irrigation during prolonged dry spells. You won't find a plant that will thrive in more situations.
Growing St. John's Wort herb in a location with too much sun can lead to leaf scorch, while too much shade reduces the number of flowers. The best location is one with bright morning sunlight and a little shade in the hottest part of the afternoon.
If your soil isn't particularly fertile, prepare the bed before transplanting. Spread about 2 inches (5 cm) of compost or rotted manure over the area and dig it into a depth of at least 8 inches (20 cm). Transplant the shrubs into the garden, setting them at the height at which they grew in their containers. They grow only 1 to 3 feet (30 to 90 cm) tall with a spread of 1.5 to 2 feet (45 to 60 cm), so space them 2 to 3 feet (60 to 90 cm) apart. Water slowly and deeply after planting and keep the soil moist until the transplants are well-established… – See more at: How to Grow and Care for St. John's Wort.