Koster's curse

Native to tropical America, Koster's curse is a highly invasive shrub that generally grows to about 2m but can reach up to 5m tall. It forms dense thickets that can smother plantations, pastures and native vegetation. It is a serious pest in at least 16 countries, including Hawaii, Fiji and Indonesia.

An infestation of Koster’s curse was found near Julatten in 2001.

Koster’s curse has the potential to spread rapidly over many areas of Australia where conditions are suitable, including the Northern Territory, northern New South Wales, and much of north-east Queensland.

Koster's curse is a restricted invasive plant under the Biosecurity Act 2014.

Scientific name

Clidemia hirta


  • Perennial shrub, generally 50-200cm tall.
  • Leaves are elliptical, 8-10cm long, arranged in opposite pairs, with distinctive veins giving 'quilted' appearance
  • Leaves and stems are covered in stiff, reddish-brown hairs.
  • Flowers are small, white, 1-1.5cm in diameter, produced in clusters in leaf forks.
  • Berries are hairy and turn dark purple when mature.


  • Prefers humid tropical lowlands and waterways.


  • Infestations have been found in North Queensland between Mossman and Tully.

Life cycle

  • Mature bush can produce thousands of purple berries and produce seeds all year.
  • Flowers throughout year.
  • Reproduces vegetatively (from cuttings, detached leaves and stems).
  • Tolerates a range of environmental conditions and reaches full maturity in less than 12 months.



  • Forms dense thickets that smother native vegetation.


  • Smothers plantations and pastures.
  • Potential to cause millions of dollars damage to primary production, irreversible damage to sensitive habitats and native plant communities.

How it is spread

  • Spread by fruit-eating birds and mammals.
  • Also spread by water, machinery and vehicles


  • New infestations must:
    • be reported to Biosecurity Queensland on 13 25 23
    • be identified and removed

Legal requirements

  • Koster's curse is a restricted invasive plant under the Biosecurity Act 2014.
  • It must not be given away, sold, or released into the environment without a permit.
  • The Act requires everyone to take all reasonable and practical steps to minimise the risks associated with invasive plants and animals under their control. This is called a general biosecurity obligation (GBO).
  • At a local level, each local government must have a biosecurity plan that covers invasive plants and animals in its area. This plan may include actions to be taken on certain species. Some of these actions may be required under local laws. Contact your local government for more information.

Further information