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Balloon vine (Cardiospermum grandiflorum)

Balloon vine is an introduced, highly invasive perennial that is naturalised in New South Wales, Queensland, South Australia and Western Australia. It smothers native vegetation and can add enough weight to trees and forest edges to cause them to collapse.

Key facts

Type: Weed, vine and creeper.

Native to: Tropical Asia, Africa, America and the West Indies.

Established in: QLD, NSW, SA, WA.

Other names: Heart-seed Vine, Large Balloon Creeper, Showy Balloon Vine.

Best time to act: It generally flowers in summer, though it can flower at any time of year; fruits ripen and turn light brown in autumn, and follow-up control is critical over the following 18 months.

Identification

  • A scrambling vine with soft green, hairy stems that can grow up to 10 metres long, often with red markings and a woody base.
  • Its soft, hairy leaves are divided into nine coarsely toothed leaflets, arranged in three groups of three.
  • Tendrils emerge from the leaf axils or below the flowers and help the vine climb.
  • Small clusters of white flowers have four petals and yellow stamens.
  • Its distinctive papery, balloon-like capsules are green when young and turn straw-brown as they age; each has three compartments containing one seed.
  • Look-alike: Native Slender Grape (Cayratia clematidea) has berries, five leaflets and hairless stems, unlike Balloon Vine’s papery capsules, nine leaflets and hairy stems.
  • Look-alike: Small Balloon Vine (Cardiospermum halicacabum varieties) has smaller capsules than Balloon Vine.

Where it grows

In Australia it occurs in coastal and subcoastal areas, especially moist forests and woodlands, waterways, gullies, roadsides and disturbed sites in New South Wales, Queensland, South Australia and Western Australia.

Why it matters

  • It climbs over trees and other vegetation, forming a thick curtain that blocks light and prevents photosynthesis.
  • It can smother and kill trees, shrubs and ground-cover plants.
  • The weight of dense growth can cause forest edges or canopies to collapse, creating conditions for further weed invasion.
  • It may invade orchards, horticultural crops, forestry, roadsides, grassy areas and neglected gardens.

How it spreads

  • Seeds disperse by wind and water, and the buoyant fruits can carry seeds downstream over large distances.
  • Dumping garden waste at remnant bushland sites has contributed to its spread.
  • It can regrow from root fragments, and seeds may remain viable for up to 18 months.

Control options

  • Hand-pull small seedlings, ensuring the taproot is removed; for larger vines, cut the stems and remove the taproot.
  • For larger plants that cannot be removed by hand, systemic herbicides are an option; consult APVMA chemical information and use registered herbicides according to their directions.
  • Older vines can be injected with herbicide or treated by cutting and swabbing; scraping and painting with herbicide is also described for young and mature plants.
  • Do not pull vines from large infestations in trees, as this may damage native vegetation and small fauna; remove and dispose of seeds, and follow up for 18 months to check for regrowth and new seedlings.

Hygiene and washdown

  • Remove and dispose of all seeds to help prevent further spread.
  • 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: 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: 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.

  • 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
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development

Sources