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Annual thunbergia (Thunbergia annua)

Annual thunbergia has not yet been found in Australia, but could become a major threat in tropical and subtropical areas if introduced. It can threaten native vegetation and degrade creek and river banks.

Key facts

Type: Weed, herb.

Native to: Arid parts of northern Africa.

Established in: .

Identification

  • An erect annual herb that grows up to 35 cm tall.
  • It is not a climbing vine.
  • Smooth leaves grow in opposite pairs along the stem.
  • The flowers are white, about 2 cm long, and may have a cream centre.
  • Look-alike: Thunbergia is listed as a similar species; Thunbergia grandiflora is also noted as a similar species.

Where it grows

It prefers frost-free locations and could spread across tropical and subtropical areas.

Why it matters

  • It could threaten remnant vegetation in the Wet Tropics.
  • It can degrade the banks of creeks and rivers.
  • It threatens native vegetation.

How it spreads

  • Seeds are spread by natural and human processes.
  • Root pieces can move along riverbanks during floods.
  • Root pieces can also spread in earth removed from infested sites for fill or other soil use.

Control options

  • Contact Biosecurity Queensland before undertaking any preventative or control actions.
  • Report any sighting immediately online, by calling Biosecurity Queensland on 13 25 23, or by calling the Exotic Plant Pest Hotline on 1800 084 881.
  • Do not keep, move, give away, sell, or release annual thunbergia into the environment.
  • Take actions reasonably likely to minimise the biosecurity threat, and do not take actions reasonably likely to worsen it.

Hygiene and washdown

  • Do not move earth from infested sites for fill or other soil use, as it can carry root pieces.
  • Be aware that seeds can be spread by human processes.
  • 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: Prohibited matter. Report it to Biosecurity Queensland on 13 25 23 within 24 hours and do not move or deal with it. 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: Not declared. Not on the NT A to Z weed list, and Weeds Australia does not list it as declared in the NT. Check the NT declared weeds list before moving or planting it.
  • 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.

Sources