*Hypericum perforatum

Family Clusiaceae

St John’s Wort

Erect, several branched herb to 1 m high with long taproot. Spreads by adventitious roots. New aerial growth arises from crowns and rhizomes. Longevity indefinite.

Flowers: Yellow, October - March.

Fruit: Sticky 3-celled capsule, 5 – 10 mm long.

Seed: Small brown 1 mm long. Single plant reported to produce 33 000 seeds in one season. Mature April – May. Seeds may lie dormant in the soil for 6 – 10 years.

Gallery images:  Seed, seedling, rootstock, resprout.


  • Native of Asia, Europe and Africa.
  • Common weed of woodland, grassland and roadsides in full sun.
  • Frequently found in woodland and grasslands at the Australian Botanic Garden.
  • Major woodland weed at Mount Annan, some controlled spraying is done.
  • Resprouts after fire.
  • Seed reported to be eaten by Crimson Rosella Platycercus elegans.

Recent observations

  • Actively growing in winter (June 2006)

Asterisk * indicates exotic species naturalised at the Australian Botanic Garden.

Ecology of Cumberland Plain Woodland

Hypericum perforatum plant

Hypericum perforatum flower

Hypericum perforatum fruit