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Leafy spurge (Euphorbia esula)

Leafy spurge is a serious pasture and rangeland weed overseas and would be a significant biosecurity concern if found in Australia. It can displace useful forage, is unpalatable to many animals, and persists through extensive roots that readily regenerate.

Key facts

Type: Weed, herb.

Native to: Europe and Asia.

Established in: .

Other names: Wolf's milk, Leafy euphorbia.

Best time to act: Look for plants when the yellow bracts are visible in spring to early summer, treat from early bud to first bloom, and check for regrowth later in the season.

Identification

  • A perennial herb with erect stems about 45 to 90 centimetres tall, arising from a crown just below the soil surface.
  • Its narrow, alternate leaves crowd along the stems and are yellow-green; they may turn red in cold weather.
  • Yellow bracts appear near the tips of short branches, with small, inconspicuous green flowers that have no petals.
  • Broken leaves, stems and roots exude an irritating milky sap.
  • The seeds form in capsules that can burst when ripe, scattering grey to brown seeds.
  • Look-alike: Other spurges (Euphorbia species) can look similar; check the combination of narrow alternate leaves, yellow bracts and milky sap before identifying a plant.

Where it grows

It favours open pasture and rangeland, particularly where grazing removes competing vegetation.

Why it matters

  • Dense infestations reduce pasture and rangeland forage by displacing more useful plants.
  • The plant is unpalatable to many animals and toxic to some, so grazing animals may avoid it.
  • Its milky sap is irritating, and its extensive, persistent roots make established infestations difficult to control.

How it spreads

  • Ripe seed capsules can burst and scatter seeds; seed can also be carried in hay and moved with soil or by animals.
  • Root and crown buds can produce new growth, including from broken root pieces moved during cultivation or in contaminated soil.

Control options

  • For isolated young plants, remove the crown and as much root as possible before seed set; contain seed heads and do not leave root fragments on site.
  • For larger infestations, use an integrated approach, such as competitive pasture establishment and repeated control of regrowth.
  • Use herbicides only when registered for the intended use or authorised by an APVMA permit, and follow the product label and relevant state or territory requirements.
  • Follow up over successive growing seasons, and promptly report suspected plants to the state or territory biosecurity agency.

Hygiene and washdown

  • Clean soil and plant material from machinery, tools, boots and other gear before leaving an infested area, taking care to remove root fragments and seeds.
  • Avoid moving contaminated soil or fodder from the 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): National priority exotic pest. On the National Priority List of Exotic Environmental Pests, Weeds and Diseases, so any new detection should be reported straight away.
  • 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: 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.

Sources