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Madagascar rubber vine (Cryptostegia madagascariensis)

Madagascar rubber vine is an introduced plant recorded as a garden plant or naturalised weed in Western Australia, the Northern Territory and Queensland. It is a concern because it can pose threats similar to rubber vine and may cross-breed with it.

Key facts

Type: Weed, vine and creeper.

Native to: Southwestern Madagascar.

Established in: QLD, WA, NT.

Other names: rubber vine.

Best time to act: Look for plants when flowering or carrying pods, and treat them while actively growing and before pods mature.

Identification

  • It is a woody shrub or climber that can grow over other vegetation.
  • Broken or scratched stems exude milky sap.
  • The leaves are glossy and paired opposite one another on the stems.
  • Its trumpet-shaped flowers are slightly smaller and a deeper pink than those of rubber vine.
  • It can be difficult to distinguish from rubber vine, so seek expert identification if unsure.
  • Look-alike: Rubber vine (Cryptostegia grandiflora) is very similar; its flowers are generally larger and lighter, ranging from light purple to white.

Where it grows

In Australia it occurs in gardens and as a naturalised weed in Western Australia, the Northern Territory and Queensland.

Why it matters

  • It can escape from gardens and pose threats similar to rubber vine.
  • Rubber vine smothers native vegetation and threatens biodiversity, waterways, woodlands and rainforests; Madagascar rubber vine is considered to pose similar threats.
  • It could cross-breed with rubber vine.

How it spreads

  • Its seeds have silky hairs that can catch the wind and carry them away from the parent plant.
  • Seeds may also be moved in water or in mud attached to vehicles, machinery and animals.

Control options

  • Confirm the plant’s identity before control, and check with the relevant state or territory biosecurity agency about local requirements and suitable methods.
  • Remove seedlings and small plants, including roots where practical, and collect pods or seed-bearing material so it cannot spread.
  • For larger plants, use a suitable registered herbicide according to its label; cut-stump treatment may suit woody plants, while foliar or basal-bark treatment may suit smaller plants.
  • Inspect treated areas regularly and remove regrowth and new seedlings before they produce seed.

Hygiene and washdown

  • Check and clean vehicles, machinery, footwear and other gear to remove mud, seeds and plant material before leaving an infested site.
  • Avoid moving soil or seed-bearing material to clean areas, and clean equipment used in waterways before moving it between sites.
  • 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: Restricted matter, category 3. Do not give it away, sell or release it into the environment. 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: Declared pest (no control category). Declared pest in WA without a control category, so there is no state-wide control requirement, but movement and keeping rules can still apply.
  • Tasmania: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Declared weed, Class A. Class A: to be eradicated. All declared weeds are also Class C, so they must not be brought into the NT.
  • 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