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Chinese violet (Asystasia gangetica)

Chinese violet is an aggressive weed identified as one of 17 sleeper weeds that could have nationally significant agricultural impacts if it spreads. It can form dense mats that smother herbaceous vegetation and reduce habitat for native plants and animals.

Key facts

Type: Weed, herb.

Native to: Africa (subspecies micrantha).

Established in: QLD, NSW, WA, NT.

Other names: Philippine violet.

Best time to act: Look for it year-round, and act early; if slashing, do so before seed set.

Identification

  • It starts as a spindly herb about 1 metre tall and can grow into a mat.
  • Stems can root where their nodes touch the soil, and fallen stems can form new plants.
  • Its tubular flowers are white with purple markings on the inside of the lower surface.
  • Fruits are up to 3 centimetres long, green at first and brown when ripe; they split explosively and fling out four seeds.

Where it grows

In Australia it is recorded in NSW, NT and QLD, including on coastal sandy soils in vacant residential areas, along fences, in neglected garden beds, and on roadsides and crown land.

Why it matters

  • It can smother vegetation in the herbaceous layer, reducing habitat for native plants and animals and lowering biodiversity.
  • It is a troublesome weed in tropical crops such as coffee, oil-palm and rubber, where it competes for soil nutrients and increases management costs.
  • It could become an agricultural weed in Australia, with potential impacts on crops including soybeans, vegetables, cut flowers and oil-tea tree.

How it spreads

  • Explosively splitting fruits fling seeds some distance, and stems can root at nodes that contact soil.
  • Plant fragments and seeds can be spread through garden-waste dumping and garden plantings, as well as agricultural, gardening, mining and roadwork activities.

Control options

  • Prioritise early detection and eradication, and follow up over a number of years to manage the soil seedbank and prevent new infestations.
  • Hand-weed small infestations with care, and dispose of plant material correctly because seeds and broken stems can establish new plants.
  • Slashing before seed set may help, but clean equipment carefully afterwards; avoid cultivation.
  • Get expert advice before attempting control, and report new outbreaks promptly to the relevant state or territory weed agency or local council.

Hygiene and washdown

  • Clean slashing equipment carefully to avoid spreading seeds or plant fragments.
  • Handle and dispose of garden waste and pulled plant material carefully, as seeds and broken stems can establish new plants.
  • 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): National Environmental Alert List. One of 28 weeds named on the National Environmental Alert List as early-stage invaders with serious potential to harm the environment.
  • 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: Biosecurity zone. A biosecurity zone applies in parts of NSW, with mandatory control inside the zone. 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
  • 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