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Golden rain tree (Koelreuteria elegans)

Golden rain tree is a cultivated ornamental that has become naturalised in parts of south-eastern Queensland and north-eastern New South Wales. It is regarded as an environmental weed in those regions and is a potential environmental weed in the Northern Territory and Western Australia.

Key facts

Type: Weed, tree.

Native to: Taiwan.

Established in: QLD, NSW.

Other names: Chinese flame tree, Chinese rain tree, Flame gold, Flamegold.

Best time to act: Look for flowering trees in late spring or early summer and treat before capsules mature, with follow-up checks during and after the late-summer and autumn fruiting period.

Identification

  • A medium-sized tree, usually 5–12 m tall, with a trunk covered in rough, furrowed greyish-brown bark.
  • Its very large leaves are twice-compound, with several branches bearing 8–17 leaflets each.
  • In late spring or early summer, large branched clusters of bright yellow flowers appear at the ends of branches.
  • The inflated, three-sided papery capsules turn from bright red or rose-purple to pink and then brown as they mature; they usually contain six black seeds.
  • Look-alike: Koelreuteria paniculata has once-compound leaves with larger leaflets, usually 7–15 cm long, and slightly elongated fruit; golden rain tree has twice-compound leaves and oval-shaped fruit.

Where it grows

In Australia it can grow along roadsides and in disturbed sites, waste areas, parks, urban bushland, riparian vegetation, gullies, forest margins and open woodlands in subtropical, tropical and warmer temperate regions.

Why it matters

  • It is regarded as an environmental weed in south-eastern Queensland and north-eastern New South Wales, and as a potential environmental weed in the Northern Territory and Western Australia.
  • It is on the Alert List for Environmental Weeds, which identifies non-native plants with the potential to seriously degrade Australia's ecosystems.
  • Seedlings can germinate en masse beneath parent trees.

How it spreads

  • Deliberate cultivation has been a main means of introducing it to new areas.
  • Seeds are carried by wind while enclosed in the light, papery fruit, and may also be spread by water.
  • Dumped garden waste and birds may also contribute to its spread.

Control options

  • Remove small seedlings by hand or with suitable tools, taking care to remove the roots and avoid disturbing nearby vegetation.
  • For larger trees, use an appropriate method such as cut-stump treatment only with a herbicide registered for the use and in accordance with its label; use suitably trained operators where required.
  • Inspect treated sites and nearby areas for new seedlings and regrowth, and remove or treat them promptly.
  • Check with the relevant state or territory biosecurity agency for current local advice and any applicable requirements.

Hygiene and washdown

  • Clean vehicles, machinery, boots and tools after working around fruiting trees, and avoid carrying the papery fruit or seeds to new sites.
  • Do not dump garden waste containing fruit or seeds in bushland or other unmanaged areas.
  • 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): National Environmental Alert List. One of 28 weeds named on the National Environmental Alert List as early-stage invaders with serious potential to harm the environment.
  • 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: 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: Check NT list. There is no NT weed profile for it. Check the NT declared weeds list for its current status.
  • 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)
  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development

Sources