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Neem tree (Azadirachta indica)

Neem is naturalised in parts of northern Western Australia, the Northern Territory and Queensland, where it is regarded as an environmental weed. It is spreading into natural areas, including riparian zones, floodplains, woodlands and coastal sites.

Key facts

Type: Weed, tree.

Native to: Thought to be native to the Indian subcontinent, including India and Bangladesh, and northern Myanmar..

Established in: QLD, WA, NT.

Other names: Indian lilac, Lilac, Margosa, Neem.

Identification

  • Neem is a tree with once-compound leaves.
  • Its leaflets have sharply toothed edges.
  • It bears clusters of flowers.
  • Its fruit develops from immature green fruit to mature fruit, with a seed inside.

Where it grows

In Australia it occurs in northern coastal districts and disturbed natural vegetation, including shrublands, open woodlands, grasslands, floodplains, riparian zones and coastal sites.

Why it matters

  • Neem is regarded as an environmental weed in the Northern Territory, northern Queensland and northern Western Australia.
  • It is appearing in riparian and revegetation sites around Townsville, and seedlings have been recorded growing in dense shade.
  • There is concern about potential effects on native insect populations.
  • Neem extracts can affect some aquatic wildlife, including fish and tadpoles.

How it spreads

  • Birds and bats eat the fruit and disperse the seeds from cultivated populations into natural environments.
  • Large infestations have been reported along the Gilbert River in Queensland, in the Victoria River Downs area of the Northern Territory, and along the Ord River in northern Western Australia.

Control options

  • Check with the relevant local weed authority for site-specific advice and approved methods.
  • If herbicides are used, use registered herbicides and follow the product label.

Hygiene and washdown

  • Avoid moving neem fruit or seed in soil, vehicles or equipment, as birds and bats can disperse seed from the fruit.
  • 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: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. 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: Declared pest (no control category). Declared pest in WA without a control category, so there is no state-wide control requirement, but movement and keeping rules can still apply.
  • Tasmania: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Declared weed, Class B. Class B: growth and spread must be controlled. All declared weeds are also Class C, so they must not be brought into the NT.
  • 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)
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources