Biosecurity Spotters logo

Giant devil's fig (Solanum chrysotrichum)

Giant devil's fig forms dense thickets that can invade grazing land and outcompete native plants and pasture grasses. Its sharp prickles can injure people and animals, and the plant contains toxins.

Key facts

Type: Weed, shrub.

Native to: Mexico and Central America.

Established in: QLD, NSW, VIC, SA.

Best time to act: Treat actively growing plants; flowers are present from autumn to spring.

Identification

  • It is a prickly shrub or small tree that can grow up to 4 m tall.
  • Its leaves are hairy underneath, have 7–13 lobes, and can be 17–30 cm long.
  • Prickles are usually sparse and occur on stems, leaf stalks and leaf mid-veins.
  • Small white, star-shaped flowers grow in clusters of up to 50, from autumn to spring.
  • Its round berries are 10–15 mm wide and turn yellow or orange-yellow as they ripen.
  • Look-alike: Devil's fig (Solanum torvum) has smaller leaves and flowers, and hairs on new growth that are whitish or yellowish rather than red.
  • Look-alike: Tropical soda apple (Solanum viarum) does not grow as tall, has larger fruit mottled when immature, flower clusters of up to 6, and usually longer prickles.

Where it grows

In Australia, it commonly grows in coastal areas of northern and central New South Wales, including pastures, waterways, forest edges, roadsides, parks, gardens and disturbed areas.

Why it matters

  • Dense thickets outcompete native plants and compete with pasture grasses, reducing productivity.
  • The plant contains steroidal glycoalkaloids that can be poisonous if eaten in large amounts, although there are no reported cases of poisoning in Australia.
  • Sharp prickles can injure people and animals.

How it spreads

  • Birds, flying foxes and other animals eat the fruit and spread the seeds.
  • Seeds also spread by water and contaminated soil.

Control options

  • Dig out seedlings and small plants with a mattock; cut down larger plants and dig up the roots.
  • Spot spray actively growing plants with registered herbicides, ensuring the foliage is covered.
  • Spraying does not kill seeds in fruit, so collect the fruit and ask the local council how to dispose of it.
  • Wear gloves and protective clothing to prevent prickle injuries.

Hygiene and washdown

  • Seeds can spread in contaminated soil and water, so avoid moving contaminated soil or water from infested 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): 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: Regional priority in 4 of 11 regions. Regional priority weed in Greater Sydney, Hunter, North Coast, South East. 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
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board

Sources