Biosecurity Spotters logo

Blowfly bush (Rhamnus alaternus)

Blowfly bush is widely naturalised in temperate southern Australia and is a serious environmental weed in parts of south-eastern Australia. It can form dense stands that crowd out native plants and prevent light reaching ground-cover vegetation.

Key facts

Type: Weed, shrub.

Native to: Southern Europe, north-western Africa and western Asia.

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

Other names: blow-fly bush, buckthorn, evergreen buckthorn, Italian buckthorn.

Best time to act: Flowers are produced from May to October, and fruit is mainly present during summer, making these useful seasons for locating plants.

Identification

  • A large shrub or small tree that grows up to 5 m tall.
  • Older branches have dark brown, furrowed bark; younger branches are pale brown or purplish, and young stems are greenish and hairless or finely hairy.
  • Leaves are alternately arranged, on short stalks, oval to egg-shaped, leathery and glossy dark green above, with paler undersides.
  • Leaf margins are sharply toothed, and leaves are 2–7.5 cm long and 0.5–4 cm wide.
  • Tiny greenish or yellowish-green flowers grow in dense clusters in the leaf forks; rounded berry-like fruit changes from green to red, then black or brown.

Where it grows

In Australia it grows in coastal and riparian areas, grasslands, open woodlands, dry sclerophyll forests, rocky outcrops, plantations, disturbed sites, waste areas and roadsides in temperate regions.

Why it matters

  • It crowds out and replaces native species in the shrub layer, while dense growth blocks light from ground-cover plants.
  • Its fast growth can allow it to dominate vegetation, outcompete sub-canopy species and infiltrate the canopy of low scrub.
  • It can form dense stands and may eventually exclude other vegetation.
  • It is a serious threat in parts of south-eastern Australia, including coastal dune scrub, coastal alkaline scrub and threatened coastal moonah woodlands in Victoria.

How it spreads

  • It reproduces mainly by seed, and fruit-eating birds, especially blackbirds, and other animals spread the seeds.
  • Seeds may also spread in dumped garden waste.
  • Plants re-shoot vigorously from the base when damaged.

Control options

  • Damaged plants can re-shoot vigorously from the base, so check for regrowth after work on a plant.
  • For management guidance, consult Muyt (2001), Bush Invaders of South-east Australia, pages 213–214.
  • Check plants and surrounding sites for further seedlings and regrowth after management.

Hygiene and washdown

  • Do not dump garden waste where it can reach bushland, as dumped garden waste may spread the seeds.
  • 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
  • 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
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development

Sources