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Three-flowered nightshade (Solanum triflorum)

Three-flowered nightshade is an introduced annual weed recorded in disturbed areas of eastern New South Wales, as well as Queensland and Victoria. It can occupy disturbed ground and should be managed before it produces berries and seed.

Key facts

Type: Weed, herb.

Native to: North America.

Established in: NSW, ACT, VIC, TAS, SA, WA.

Best time to act: Look for plants in summer when they flower, and treat them before the berries mature.

Identification

  • It is a sprawling annual herb with sparsely hairy stems that can grow to 1 m long and sometimes root at the nodes.
  • Its leaves are deeply lobed or divided, 2–4 cm long and 1–2.5 cm wide, with toothed or lobed edges that are recurved and thickened.
  • The leaves and stems have simple hairs, and the plant has no prickles.
  • Small clusters of 1–3 star-shaped flowers are white or rarely pale lavender, about 5–6 mm across.
  • The berries are 8–12 mm across and whitish green with marbling.
  • Look-alike: It may be confused with other small-leaved annual nightshades; check for the combination of a sprawling, unprickled plant, deeply divided leaves and whitish-green marbled berries.

Where it grows

In Australia it is recorded as a weed of disturbed areas in New South Wales east from Finley, and also occurs in Queensland and Victoria.

Why it matters

  • It can establish on disturbed ground and compete with desirable plants.
  • As a nightshade, it should be treated as potentially toxic to stock; do not assume its berries or foliage are safe to eat.

How it spreads

  • It reproduces by seed contained in its berries.
  • Movement of berries, plants or contaminated soil can spread it to new sites.

Control options

  • For small patches, pull or dig out plants before berries mature, taking care to remove rooted nodes and collect the berries and plant material.
  • Dispose of removed material so berries cannot continue to mature or spread.
  • Where chemical control is appropriate, use only a herbicide registered for the plant and site, and follow the product label and any applicable permit requirements.
  • Reinspect treated areas and nearby disturbed ground for seedlings, and check with the relevant local or state biosecurity authority for current management advice.

Hygiene and washdown

  • Clean soil, berries and plant fragments from boots, tools, vehicles and machinery before leaving an infested site.
  • 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: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • 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.

  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Australian Capital Territory: Biosecurity Act 2023 (ACT), administered by ACT Biosecurity
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania
  • 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