St. Johnswort, Perforated St. Johnswort, Common St. Johnswort, Klamathweed
Hypericum perforatum L.
Hypericaceae or Clusiaceae (St. Johnswort Family)
▲ young shoots emerging in spring
▲ pre-flowering mature plant
▲▼ mature, flowering plants
▲▼ flowers
▲ flowering stem, leaves
St. Johnswort, Klamath Weed:
· creeping perennial with creeping roots and 1-2’ tall stems, unbranched below, becoming much-branched above as it begins to produce flower buds
· flowers are somewhat showy, yellow with black-dotted petals
· leaves are ovate to lanceolate, 1-3” long and about ½ as wide; leaves also have either black dots or clear dots (depending on species)
· consumption can cause photosensitivity in livestock—where skin can blister as if from severe sunburn in normal conditions; very toxic to sheep
· in moist to well-drained, sandy or rocky soils; includes both native and non-native species