Hypericum Species, Perforate St. John's Wort, Common St. Johnswort, Klamath Weed
Hypericumperforatum

Family: Hypericaceae (hy-PER-ee-KAY-see-ee)
Genus: Hypericum (hy-PER-ee-kum)
Species: perforatum (per-for-AY-tum)

Category
Herbs

Water Requirements
Average Water Needs; Water regularly; do not overwater

Sun Exposure
Sun to Partial Shade

Foliage
Deciduous

Foliage Color

Height
12-18 in. (30-45 cm)
18-24 in. (45-60 cm)

Spacing
18-24 in. (45-60 cm)

Hardiness
USDA Zone 4a: to -34.4 °C (-30 °F)
USDA Zone 4b: to -31.6 °C (-25 °F)
USDA Zone 5a: to -28.8 °C (-20 °F)
USDA Zone 5b: to -26.1 °C (-15 °F)
USDA Zone 6a: to -23.3 °C (-10 °F)
USDA Zone 6b: to -20.5 °C (-5 °F)
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)

Where to Grow
Grow outdoors year-round in hardiness zone

Danger
N/A

Bloom Color
Bright Yellow

Bloom Characteristics

Bloom Size

Bloom Time
Mid Summer

Other details
May be a noxious weed or invasive

Soil pH requirements
5.1 to 5.5 (strongly acidic)
5.6 to 6.0 (acidic)
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)

Patent Information
Non-patented

Propagation Methods
From softwood cuttings
From seed; direct sow outdoors in fall
From seed; winter sow in vented containers, coldframe or unheated greenhouse
From seed; sow indoors before last frost

Seed Collecting
Allow pods to dry on plant; break open to collect seeds