St. John's Wort

Guttiferaceae

LIFE FORM: Perennial

NATIVITY: Europe

VEGETATIVE CHARACTERISTICS:

Stiffly branched plant that grows to about 2 feet tall; small leaves with tiny translucent dots give them a mottled appearance.

FLOWERS:

Golden-yellow flowers in a flat-topped cluster produced in summer.

FRUIT/DISPERSAL AGENTS:

Spreads by seed and leafy runners.

ECOLOGICAL PREFERENCE:

Common on poor soil. Prefers trampled lawns in public parks; neglected residential and commercial landscapes; minimally maintained public parks and open space; vacant lots and rubble dump sites; abandoned grasslands (meadows); rock outcrops and stone walls; unmowed highway banks and median strips with frequent salt applications; railroad tracks with ballast substrate.

ENVIRONMENTAL FUNCTION:

Disturbance-adapted colonizer.

CULTURAL SIGNIFICANCE:

An important medicinal plant in Europe, where it is also used to protect against witchcraft spells. Included by Greek physician Pedanius Dioscorides in his five volume herbal, De Materia Medica, which was written in the first century AD and remained in active use into the 1600s.