St John’s Wort (Hypericum perforatum)

St John’s Wort

Description

  • Erect branched herb/shrub up to about 1 metre tall
  • Leaves have black dots along margins, oil glands visible when held to the light
  • Flowers bright yellow, five petals, black-dotted along margins
  • Most parts of plant have black oil glands that produce a red fluid when crushed

St John's Wort Information Link

Flowering Times

•    Spring to summer

Control Measure

•    Hand removal of isolated plants
•    Herbicides

Problems

•    Known to cause photosensitivity in livestock, resulting in loss of condition, low productivity and – in extreme cases – death
•    Prolific seeders with up to 30,000 per plant
•    Seeds can remain viable for up to 12 years

 

Hypericum perforatum

Australian Pesticides and Veterinary Medicines Authority

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