St. John's Wort

St. John's Wort, Perforated St. John's Wort, Common St. John's Wort, Klamathweed

Hypericum perforatum L.

Hypericaceae or Clusiaceae (St. John's Wort Family)

▲ young shoots emerging in spring

▲ pre-flowering mature plant

▲ ▼ mature, flowering plants

▲ ▼ flowers

▲ flowering stem, leaves

St. John's Wort, 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 1/2 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