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Mediterranean mustard (Brassica barrelieri)

Mediterranean mustard is an introduced annual that can establish in disturbed places and compete with useful plants. Correct identification and control before it sets seed help limit its persistence and spread.

Key facts

Type: Weed, herb.

Native to: Mediterranean region, including parts of southern Europe and North Africa.

Established in: WA.

Other names: Barrelier’s mustard.

Best time to act: Look for plants during their growing and flowering period, and treat them before the seed pods mature.

Identification

  • An upright annual herb that can grow to about 1 metre tall.
  • Lower leaves are rough and deeply lobed, with a larger terminal lobe; upper leaves are narrower and less divided.
  • Small yellow flowers have four petals and are carried in clusters near the ends of stems.
  • The flowers develop into narrow seed pods held close to the stem, each with a pointed beak.
  • Look-alike: It resembles other yellow-flowered mustards, including wild turnip and wild radish; check the leaf shape and the narrow pods with their pointed beaks to confirm identification.

Where it grows

In Australia it can grow in disturbed ground, including roadsides, waste places and agricultural land.

Why it matters

  • It can compete with crops, pasture plants and native vegetation for space and resources.
  • If plants set seed, they can contribute to a persistent seed supply and make later control more difficult.
  • Dense growth may hinder land management and restoration work.

How it spreads

  • Seeds can be moved in contaminated soil, on vehicles and machinery, or on boots and other equipment.
  • Seed may also be spread when mature plants or pods are moved during slashing, cultivation or other site work.

Control options

  • For small infestations, pull or dig out plants and remove them before seed pods mature; dispose of plants so they cannot shed seed.
  • For larger infestations, use only herbicides registered for the target weed and site, and follow the product label and relevant safety requirements.
  • Plan control before seed set and revisit treated areas to remove survivors and new seedlings.
  • Check with the relevant state or territory biosecurity agency for current identification, reporting and control advice.

Hygiene and washdown

  • Clean soil and plant material from vehicles, machinery, boots and equipment before leaving an infested site, and avoid moving contaminated soil or fodder.
  • 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