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Harungana (Harungana madagascariensis)

Harungana is a serious environmental weed in the wet tropics of North Queensland, especially around Babinda. It forms dense thickets that exclude native plants and may become a permanent part of tropical rainforest.

Key facts

Type: Weed, tree.

Native to: Tropical Africa, Madagascar and Mauritius.

Established in: QLD.

Other names: Haronga, Dragon's-blood tree, Orange-milk tree, Praying Hands Bush.

Best time to act: In North Queensland, plan treatment before flowering, which is recorded from August to November and peaks in October and November; fruit is produced from October to December.

Identification

  • An erect, multistemmed shrub or tree growing 4–20 metres tall, with rough, scaly and often vertically fissured bark.
  • Young stems have star-shaped hairs, and damaged leaves or stems exude brilliant orange sap.
  • Opposite, egg-shaped leaves are 6–20 cm long, dotted with black glands, glossy dark green above and densely covered in rusty-coloured hairs underneath.
  • Small, sweetly almond-scented white or cream flowers grow in dense heads at the ends of shoots.
  • Rounded, berry-like fruits are 2–4 mm across, orange to yellow-brown at first and deep red to brown when mature.

Where it grows

In Australia, Harungana is concentrated around Babinda in coastal north Queensland's wet tropics, including the lower slopes of the Bellenden Ker Range and western slopes of Graham Range, with outlying populations south to Bramston Beach and Miriniwinni.

Why it matters

  • Large numbers of seeds germinate together and establish rapidly.
  • Dense thickets can exclude native species and form a monoculture over several hectares.
  • It can destroy habitat for native fauna and has been found 2½ km inside undisturbed rainforest in gaps created by tree falls and landslips.
  • It could spread to other parts of tropical Australia with favourable climate and rainfall.

How it spreads

  • Fruit-eating birds, fruit-bats, water and machinery may disperse its large quantity of seeds.
  • It can also spread laterally as suckers develop from its roots.

Control options

  • Hand-pull or dig out seedlings and young trees where practical.
  • Cut trees down and treat the stumps with registered herbicides; foliar application may be used for regrowth, and stem injection may be preferred for trees.
  • Treat before flowering to reduce flowering and fruit production, and monitor and follow up on regrowth.
  • Avoid mechanical disturbance, which encourages seed germination; in Queensland, Harungana is a restricted invasive plant and must not be given away, sold or released into the environment.

Hygiene and washdown

  • Because machinery can spread Harungana seeds, clean machinery and equipment before moving from infested sites.
  • Inspect and clean vehicles, plant and footwear before leaving an infested area, paying attention to tyres, radiators, belly plates, tracks and floor mats.
  • Wash down at a designated bay where runoff is contained and can be monitored for seedlings.
  • Record each washdown so the client has evidence of clean entry and exit.

Classification by state

  • Australia (national): No national listing. Managed under state and territory law.
  • Queensland: Restricted matter, category 3. Do not give it away, sell or release it into the environment. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Not a priority weed. Not a state or regional priority weed in NSW. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • Tasmania: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Not declared. Not on the NT A to Z weed list, and Weeds Australia does not list it as declared in the NT. Check the NT declared weeds list before moving or planting it.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)

Sources