Tree Killers: Common Buckthorn

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  • Common English name: Common Buckthorn
  • Other names: buckthorn, purging buckthorn, European buckthorn
  • Latin (scientific) name: Rhamnus cathartica

Threat type

150x150 plants

History in Canada

  • brought to North America in the late 1800’s for landscape planting
  • most abundant in southern Ontario but also occurs west to Saskatchewan and east to Prince Edward Island
  • still available from nurseries


  • large shrub or small tree (up to 6 m or 20 ft tall) with thorny twigs and strongly-veined leaves that remain on the plant late in the fall
  • male and female flowers on separate individuals
  • female tree produces large numbers of dark berry-like fruits, singly or in small groups, along younger branches at the base of the oval-shaped leaves
  • leaves have serrated edges unlike Glossy Buckthorn whose leaves have smooth edges
  • leaves come out early in spring and remain on the plant until late fall which shades out most native plants
  • fruits, leaves, and bark are cathartic (purging) to most animals but birds eat them readily
  • birds are largely responsible for the spread of Common Buckthorn since the seeds within the fruit pass through the bird without damage
  • seeds remain viable for up to three years and have a high germination rate
  • tolerates a wide range of upland habitats including forests and woodland edges

Impact on Trees

  • grows in dense stands that suppress native tree seedlings due to heavy shade
  • may produce a substance that inhibits the growth of other species

What can be done to control this tree killer?

  • cutting or girdling stems followed by herbicide application to the cut stems or later removal of sprouts that develop after cutting or girdling
  • grows later in the season than most native plants so fall application of herbicide can be effective with little impact on nearby native species
  • annual or biennial burns
  • mowing younger stands
  • several years of control are needed since seeds are unaffected by the above methods and seedlings can quickly recolonize an area

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