Biosecurity Spotters logo

Night-scented stock (Matthiola longipetala)

This introduced garden escape is naturalised in South Australia and Victoria, where it can become a weed in farmland. It can compete strongly with cereal crops, reduce yields and contaminate seed and hay, lowering their value and marketability.

Key facts

Type: Weed, herb.

Native to: South-eastern Europe, western Asia, the Arabian Peninsula, the Caucasus and northern Africa.

Established in: VIC, SA.

Other names: Nightstock, Night Stock, Evening Stock, Two-horn Stock.

Best time to act: Look for germination mainly in autumn and winter, and aim to control plants before they set seed; flowering is generally in spring but can occur erratically throughout the year.

Identification

  • An annual or biennial herb growing to about 500 mm tall, with stems and leaves covered in minute, star-shaped hairs.
  • Lower leaves are stalked, 90–100 mm long and toothed to pinnately lobed; upper leaves have fewer or no lobes.
  • It has four pink to purple petals, sometimes paler at the centre, and flowers that open at night and produce a strong perfume.
  • Its erect to spreading, narrow fruits are 35–150 mm long and have two horn-like projections, 2–10 mm long, at the tip.
  • The numerous ripe seeds are small, oblong and brownish, about 1.8–2.7 mm long.
  • Look-alike: Common Stock or Gilliflower (Matthiola incana) also has fruits with horn-like projections, but its horns are up to 3 mm long, compared with up to 10 mm in Night-scented Stock.
  • Look-alike: Common Stock is a longer-lived perennial with unlobed leaves and flowers that open during the day; Night-scented Stock has variously lobed lower leaves and flowers that open in the evening.

Where it grows

In Australia it occurs in farmland, including pasture and crops, and on roadsides, and is naturalised in South Australia and Victoria.

Why it matters

  • It can become a significant weed in cereal crops because it produces many seeds.
  • It competes strongly with cereals and can reduce yields.
  • It can contaminate seed and hay, reducing their value and marketability.
  • It is an occasional garden escape in urban areas and disturbed sites, and is not known as a weed of native ecosystems outside disturbed native areas.

How it spreads

  • It reproduces by seed, and seeds are often dispersed in contaminated agricultural produce.
  • Seeds can also spread in soil carried on vehicles, machinery and tools, or from garden ornamentals.
  • Its high seed production gives it the potential to increase rapidly in cereal crops.

Control options

  • Prevent seed set to help limit spread, and use good plant hygiene to avoid moving seed-contaminated soil.
  • Use registered herbicides appropriate for crucifer weeds; herbicides routinely used in cereal crops may not control it effectively, so an additional treatment may be needed.
  • Isolated plants can be removed by hand, but remove them from the site if unripe fruits are present, as fruits and seeds can mature after uprooting.
  • Repeat manual removal at least every 8–10 weeks; if plants have set seed, follow up to control further germinations. Mechanical control may be effective against young plants in cropping, though it is not widely reported.

Hygiene and washdown

  • Clean soil and seeds from vehicles, machinery and tools before moving between infested and uninfested areas.
  • Check agricultural produce for contamination, as seeds are often dispersed in it.
  • 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: Declared plant. Depending on the declaration, it can be an offence to move it on public roads or sell it, and landowners may be required to control it on their land.
  • Western Australia: Declared pest (C1), prohibited. C1 Exclusion: to be kept out of WA, or out of the parts of WA where it is not established. Report any sighting to DPIRD. It must not be brought into WA (prohibited organism).
  • 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.

  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board

Sources