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Candyleaf (Stevia ovata)

Candyleaf can form dense stands and may out-compete native pasture used for grazing, although the scale of its impacts is not well established. In Queensland it is a category 3 restricted invasive plant, and landholders must manage its impacts and take reasonable and practical measures to minimise biosecurity risks.

Key facts

Type: Weed, herb.

Native to: Tropical America, from the mountains of Texas through Mexico to Ecuador and Peru..

Established in: QLD.

Best time to act: Inspect when the white flower clusters make plants easier to spot, and treat before plants can set seed.

Identification

  • A perennial herb, usually 40–80 cm tall.
  • Small white flowers grow in clusters.
  • Leaves are variable in shape and 3–6 cm long.
  • Leaves are generally in opposite pairs along the stem, but may sometimes be alternate.

Where it grows

In Queensland it is known near Ravenshoe on the Atherton Tableland, in open disturbed rocky sites, roadsides, woodlands and native pastures, generally on high-altitude mountains.

Why it matters

  • It can form dense stands and invade disturbed and undisturbed land.
  • It can out-compete native pastures that may be used for grazing.
  • The scale of its impacts is not well established, but it could become a significant pest.

How it spreads

  • Do not give away, sell or release candyleaf into the environment; these actions are prohibited for this restricted plant in Queensland.
  • Avoid moving candyleaf or potentially contaminated soil from infested areas to clean sites.

Control options

  • For small patches, physically remove plants and collect the plant material, taking care not to spread it during handling; follow local council advice on disposal.
  • Where herbicide is suitable, use only a product registered for the intended use and follow its label and any applicable requirements.
  • Recheck treated sites and follow up regrowth or new plants.
  • In Queensland, take all reasonable and practical measures to minimise biosecurity risks and contact your local council or state biosecurity agency for advice.

Hygiene and washdown

  • Clean soil and plant material from boots, tools, vehicles and machinery before leaving infested sites.
  • Avoid carrying soil or plant material from infested areas to uninfested 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: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • 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)

Sources