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White moonflower (Ipomoea alba)

White moonflower is an introduced ornamental that has escaped cultivation in Australia, including in south-eastern Queensland and New South Wales. It can smother native vegetation and is a serious environmental weed in rainforest and other moist habitats.

Key facts

Type: Weed, vine and creeper.

Native to: North and South America, including the Caribbean.

Established in: QLD, NSW, WA.

Other names: Moonflower vine, Moon vine, Giant moonflower, Tropical white morning glory.

Best time to act: Look for it year-round, with flowers easiest to spot at night, and treat infestations promptly before seed capsules can spread.

Identification

  • A fast-growing, twining vine that can climb to about 10 m, with milky sap and stems that may be smooth or have soft prickles.
  • Leaves are usually heart-shaped or broadly ovate, about 10 to 20 cm long, with smooth edges that may be angular or divided into three lobes.
  • Large, fragrant white flowers with greenish bands open at night; the trumpet-shaped flowers are about 7 to 12 cm across.
  • The oval seed capsules are about 2.5 to 3 cm long and contain white, brown or black seeds.
  • Look-alike: Ipomoea obscura has similar foliage and white flowers, but its flowers are much smaller and have a shorter floral tube.
  • Look-alike: Ipomoea indica and Ipomoea purpurea can have similar heart-shaped or three-lobed leaves, but their flowers are smaller and often pink or purplish.

Where it grows

In tropical and subtropical Australia it escapes cultivation into watercourses, riparian areas, moist forests, coastal areas, urban bushland and disturbed places such as parks, roadsides and railway lines.

Why it matters

  • Climbing over other plants, it forms a dense canopy that shades native vegetation and competes for water, nutrients and sunlight.
  • It also spreads across the ground as a dense mat that inhibits the establishment and growth of other plants.
  • In Australia it invades bushland, riparian zones and watercourses, and can displace native plants in rainforests.

How it spreads

  • It spreads by seed and vegetatively, with stems producing adventitious roots and stem fragments able to grow.
  • Seeds and stem pieces can move in water, wind and dumped garden waste, and may be carried in contaminated seed crops, soil or machinery.
  • It has also been deliberately planted and sold as an ornamental.

Control options

  • Pull or hoe small seedlings, and for small infestations cut plants near the base and dig out the roots by hand.
  • For larger infestations, cut stems and treat the cut stems with a herbicide registered for the site and use, strictly following its label.
  • Return to check for regrowth and new seedlings, and treat them promptly.
  • Check with the relevant state or territory biosecurity agency for local control advice and any reporting requirements.

Hygiene and washdown

  • Before leaving an infested site, remove plant fragments and soil from vehicles, machinery, boots and equipment, and dispose of the material where it cannot regrow.
  • Do not dump garden waste or move contaminated soil 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: 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: 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
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development

Sources