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Runcinate mustard (Sisymbrium runcinatum)

Sisymbrium runcinatum is an introduced annual mustard that can establish in disturbed areas and compete with crops and pasture plants. It is most useful to identify and control plants before they set seed, to limit further spread.

Key facts

Type: Weed, herb.

Native to: Mediterranean region and western Asia.

Established in: WA.

Other names: Runcinate sisymbrium, Runcinate-leaved mustard.

Best time to act: Look for plants when they flower and fruit, and control them before the seed pods mature.

Identification

  • Look for an annual herb that grows upright or spreads outward.
  • The lower leaves are deeply divided into lobes, with the lobes pointing back towards the leaf base.
  • The upper leaves are generally smaller and less divided.
  • Small yellow flowers have four petals.
  • The flowers are followed by narrow, elongated seed pods.
  • Look-alike: Other yellow-flowered mustards, including London rocket (Sisymbrium irio), can look similar; check the leaf shape and seed pods to help distinguish them.

Where it grows

In Australia it is found in disturbed ground, including roadsides, waste areas and agricultural land.

Why it matters

  • It can compete with desirable plants for space, light, water and nutrients.
  • Where it establishes in crops or pasture, it can contribute to weed pressure and reduce the growth of useful plants.
  • Seed production can allow infestations to persist and spread into nearby disturbed areas.

How it spreads

  • Plants spread by seed, which can be moved in contaminated soil, crop material or fodder.
  • Seeds may also be carried to new sites on vehicles, machinery, boots and other equipment.

Control options

  • Hand-pull or dig out small infestations, removing the roots where practical and collecting plants before seed pods mature.
  • Use only herbicides registered for the site and target weed, and follow the product label and local advice.
  • Dispose of plants with developing seed so they cannot mature or spread, and avoid moving contaminated soil or plant material.
  • Revisit treated sites for follow-up control; report suspected new or unusual infestations to the relevant state or territory biosecurity agency.

Hygiene and washdown

  • Clean soil and plant material from vehicles, machinery, boots and tools before leaving an infested site.
  • Avoid moving potentially contaminated fodder, soil or harvested material to clean areas.
  • 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: 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.

  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development

Sources