Hypericum perforatumSt._Johns_Wort


Family: Clusiaceae (St. John’s wort).

Other Common Names: St. John’s-wort, Klamath weed, goatweed.

Origin: Eurasia.

Growth Form / Reproduction: Perennial. Seed, rhizomes below ground and creeping stems above ground.

Legal Status: Forest and Range Practices Act, Community Charters Act.

Agricultural: Invades grazed and disturbed sites. In dense stands, it reduces livestock and wildlife forage. The plant contains a toxin that causes skin irritation and blistering in light-colored livestock when they are exposed to sunlight.
Ecological: Dense stands can displace native plants.
Human: Contact with sap can cause irritation when skin is exposed to sun. Ornamental plant. Medicinal uses.

Habitat: Disturbed sites in grasslands and open forest, moist to dry fields and pastures, roadsides.

Status and Distribution: Widespread throughout the entire CIPC region, especially along major road corridors. Most common in CWHxm, CDFmm and CWHvm, present in the CWHvh, CWHdm and MHmm.

Management Strategy: This species is considered to be under biological control but some populations of the plant are out of phase with the agents. Tillage can control the plant in agricultural fields. Combinations of 2,4-D and picloram, or 2,4-D and glyphosate have produced control in the US. Several biocontrol agents are available to control large infestations. Monitor sites to confirm agents are present and the plant is not dispersing.