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Phalsa (Grewia asiatica)

Phalsa is an introduced invasive plant recorded in Queensland and the Northern Territory, and is becoming widespread in northern Queensland. Birds, animals and floodwaters can spread its seeds, allowing it to establish beyond gardens and plantings.

Key facts

Type: Weed, tree.

Native to: India, Nepal and tropical Asia, including Cambodia, Laos and Thailand.

Established in: QLD, WA, NT.

Other names: Falsa, Indian phalsa, Grewia subinaequalis, Microcos lateriflora.

Best time to act: Look for plants while they are flowering or fruiting to aid identification, and treat before fruit matures to reduce seed spread.

Identification

  • It grows as a tree or shrub, with reddish branches that have a net-like pattern.
  • Its rounded to obliquely oval leaves have serrated edges, a pointed tip and five main veins from the base, and can reach 18 cm long.
  • The leaves and young branches may be smooth or covered in soft hairs.
  • It has yellow flowers and black, fleshy, round fruit up to about 1 cm long.
  • Look-alike: Related Grewia species may look similar; check the combination of serrated, strongly veined leaves, yellow flowers and black fleshy fruit.

Where it grows

In Australia it grows in drier woodlands, drier vine thickets and coastal areas, including northern Queensland.

Why it matters

  • It is recorded as invasive in Queensland and the Northern Territory and is becoming widespread in northern Queensland.
  • It can establish in drier woodland, vine thicket and coastal habitats, where it may compete with native vegetation.
  • Seeds can pass through birds and other animals, helping the plant spread into new areas.

How it spreads

  • Birds and other animals spread seeds after eating the fruit.
  • Floodwaters can carry seeds, and ornamental plantings provide another source of spread.

Control options

  • Remove small plants by hand or with tools, taking care to remove the root system and avoid disturbing nearby vegetation.
  • For larger plants, use only herbicides registered for the target plant and site, or other approved methods, and follow the product label and local biosecurity advice.
  • Collect fruit-bearing material and dispose of it so fruit and seeds cannot spread; do not dump garden waste in bushland or waterways.
  • Revisit treated sites to check for regrowth and new seedlings, and report new or outlying infestations to the relevant state or territory biosecurity agency.

Hygiene and washdown

  • Before leaving an infested site, remove fruit, seeds and soil from vehicles, machinery, boots and other gear, and avoid moving contaminated soil or garden waste.
  • 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: 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: Not declared. Listed on the NT A to Z weed list but not declared under the Weeds Management Act 2001.
  • 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