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Desert ash (Fraxinus angustifolia)

Desert ash is an introduced tree recorded as an environmental weed in the ACT, NSW and Victoria. It is reported across the Canberra and Southern Tablelands region, including reserves, ridges, parks and waterways.

Key facts

Type: Weed, tree.

Native to: Southern Europe, North Africa and western Asia.

Established in: NSW, ACT, VIC, TAS, SA.

Other names: Narrow-leaved ash, Caucasian ash.

Best time to act: Look for the tree while it is in leaf and treat it before its seeds mature and disperse.

Identification

  • It is a deciduous tree with leaves arranged in opposite pairs along the stems.
  • Each compound leaf has several narrow, pointed leaflets with toothed edges.
  • Its seeds occur in large clusters on drooping stalks.
  • The winged seeds are slightly twisted and start pale green, turning brown as they mature.
  • Look-alike: Other ash trees, including European ash, can look similar; desert ash has notably narrow leaflets.

Where it grows

In Australia it grows in urban and disturbed areas, reserves and along waterways, and is recorded at sites across the Canberra and Southern Tablelands.

Why it matters

  • It is recognised as an environmental weed in the ACT, NSW and Victoria.
  • Established trees can compete with native plants for space, light and resources.
  • Dense growth can alter vegetation structure and the habitat available to native species.

How it spreads

  • The winged seeds can be carried by wind and may also move with water.
  • Planting as an ornamental tree can provide a source for escape into nearby natural areas.

Control options

  • Hand-pull small seedlings when the soil is moist, removing the roots, and collect seed-bearing material.
  • For larger trees, use a suitable cut-stump or other approved method with a herbicide registered for that use, following the product label and local requirements.
  • Avoid damage to nearby native plants and take particular care when working near waterways.
  • Check treated areas for regrowth and new seedlings, and report new or outlying infestations to the relevant state or territory weed agency or land manager.

Hygiene and washdown

  • Clean soil, seeds and plant material from vehicles, machinery, boots and tools before leaving an infested site, and dispose of collected material responsibly.
  • 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: Declared plant. Depending on the declaration, it can be an offence to move it on public roads or sell it, and landowners may be required to control it on their land.
  • Western Australia: Permitted, not declared. Listed as a permitted organism in WA, so it can be brought in, but it is not a declared pest.
  • 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.

  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Australian Capital Territory: Biosecurity Act 2023 (ACT), administered by ACT Biosecurity
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board

Sources