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Coastal morning glory (Ipomoea cairica)

This vigorous perennial climber has become naturalised in many Australian coastal areas after being widely cultivated as a garden ornamental. It can rapidly smother native vegetation, reducing biodiversity and displacing native animals.

Key facts

Type: Weed, vine and creeper.

Native to: Thought to originate in tropical Africa and Asia; its exact origin is unknown..

Established in: QLD, NSW, WA.

Other names: Mile-a-minute, Morning glory, Coast morning glory, Five-leaved morning glory.

Best time to act: It flowers throughout the year; cut-stump or stem-scraping treatment is described for vines that are actively growing and not stressed.

Identification

  • A vigorous perennial climber with trailing or twining stems that are hairless or nearly hairless.
  • Stems exude white sap when cut and can root at their nodes.
  • Smooth leaves are deeply divided into 5 to 7 lobes, with the longest lobe 4 to 9 cm long.
  • Showy, funnel-shaped flowers are usually violet to purplish-violet, with a darker throat, and are 6 to 8 cm across; white or pink flowers are rare.
  • The fruit is a roughly spherical capsule 9 to 11 mm across; its egg-shaped seeds are 4 to 5 mm across and densely hairy.

Where it grows

In Australia it occurs mostly in coastal and subcoastal areas, especially riverbanks, and also grows in disturbed sites, rainforest margins, open woodlands, gardens, coastal dunes and other riparian areas.

Why it matters

  • It can form dense ground mats or climb into the canopy, sometimes reaching 4.5 m.
  • It can smother native vegetation, reducing biodiversity and displacing native animals through habitat destruction.
  • The weight of the vine can crush plants it grows over, and it can grow over fences and smaller structures.
  • It also affects urban and peri-urban sites, including abandoned areas, gardens, roadsides, fence-lines, creeks and drains.

How it spreads

  • Seeds are dispersed by water and birds.
  • Stem nodes can root, and stem fragments can establish new plants when transported elsewhere.
  • Spread can occur through dumped garden waste, machinery, and broken stems carried by floods or waterways.

Control options

  • Physical removal is possible; remove the stem, crown and roots, as material left in the ground can regrow.
  • Remove stem fragments and viable seeds from the site to prevent regrowth and germination.
  • Registered herbicides can be applied as a foliar spray where the plant forms dense groundcover, or by scraping and painting individual vine stems.
  • Cut-stump or stem-scraping treatment is described for actively growing vines that are not stressed; use registered herbicides according to their approved directions.

Hygiene and washdown

  • Do not move vine stems or garden waste to other sites, as stem fragments can root and form new plants.
  • Check machinery for stem fragments and avoid transporting them; broken stems can also spread through waterways and floods.
  • 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