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St John's Wort

St John's Wort flower
St John's wort close-up of flower
St John's Wort
St John's wort flowers


General information

St John´s wort (Hypericum perforatum) is a perennial herb, native to Europe, western Asia and North Africa. It is grown for use as an anti-inflammatory, astringent and antiseptic. It is an invasive weed in more than 20 countries and has the potential to spread across cooler, upland areas of southern Queensland.

St John's wort is not a declared plant under Queensland legislation, however its control is recommended.

Scientific name

Hypericum perforatum
Impacts
  • invades woodlands and pastures
  • poisonous to livestock 
Description
  • a perennial herb
  • stems 30-120 cm tall in spring and summer. 
  • leaves are dotted with tiny translucent, black oil glands
  • flowers are bright yellow, 1-2 cm in diameter with five petals
Habitat and distribution
  • prefers rangelands, pastures, fields, roadsides and forest clearings in temperate regions with cool, moist winters and dry summers
  • grows best in open, disturbed sites and on slightly acidic to neutral soils
  • found in all states of Australia except the Northern Territory
  • small populations near Stanthorpe and Toowoomba in Queensland
Control
  • biological control with Chrysolina beetles has been used in Australia
  • other insects are used in biological control programs in North America and New Zealand
Declaration details
  • not a declared plant under Queensland legislation but may be declared under local government law
Further information

Page maintained by Sonia Jordan
Last updated 22 January 2009
URL: http://www.dpi.qld.gov.au/cps/rde/xchg/dpi/hs.xsl/cps/rde/dpi/hs.xsl/4790_12761_ENA_HTML.htm

© The State of Queensland, Department of Primary Industries and Fisheries 1995 - 2009.
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