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Ragwort (Senecio jacobaea)

Ragwort is a serious agricultural and environmental weed that invades pastures and native vegetation, particularly in southern Victoria. Its toxic alkaloids can cause cumulative, irreversible liver damage in grazing animals, and the plant can reduce pasture productivity.

Key facts

Type: Weed, herb.

Native to: Europe and Western Asia.

Established in: NSW, VIC, TAS.

Other names: Common Ragwort, St James Wort, Stagger Wort, Tansy Ragwort.

Best time to act: Look for rosettes mainly in autumn and spring and target them then; autumn is the preferred treatment time, while flowering peaks from late January to March.

Identification

  • It is an erect, slightly hairy or smooth herb, usually 450 to 600 mm tall but growing to about 1.5 m, and may be a biennial or short-lived perennial.
  • The first leaves form a ground-level rosette; they are dark to mid-green above and vary from toothed to deeply lobed.
  • Stem leaves are unstalked and deeply divided, and the lower leaves die as the flowering stalk emerges.
  • Bright yellow, daisy-like flower-heads grow in clusters at the top of the plant; each head is about 25 mm across.
  • The small straw-coloured to light-brown fruits are about 2 mm long; some have fine white hairs that aid wind dispersal.
  • Look-alike: It can be confused with Common groundsel (Senecio vulgaris), Commonwealth Weed (S. bipinnatisectus), Variable Groundsel (S. lautus), Fireweed (S. madagascariensis), African Daisy (S. pterophorus) and Fireweed Groundsel (S. linearifolius).

Where it grows

In Australia it occurs in NSW, SA, TAS, VIC and WA, especially in southern Victoria and Tasmania, in pastures and grasslands as well as coastal vegetation, heathland, woodland, forests, riparian areas and freshwater wetlands.

Why it matters

  • Ragwort contains alkaloid toxins that can cause cumulative, irreversible liver failure in horses and other grazing animals.
  • Dairy cattle forced to eat it can produce tainted milk.
  • Its dense foliage competes with desirable plants, reduces pasture productivity and livestock carrying capacity, and can invade native forests, woodlands and roadsides.

How it spreads

  • A plant can produce up to 250,000 one-seeded fruits in a year; heavier fruits fall near the parent, while lighter, hair-bearing fruits are carried by wind, water and animals.
  • Fruits can also spread in stock feed and mud on vehicles or machinery, and seeds can remain dormant in the soil for many years.
  • Ragwort can regrow from root or crown fragments, which may be moved in soil or on vehicles and machinery.

Control options

  • Use registered herbicides in a minimum two-year program, with applications in autumn and spring; target seedlings or first-year rosettes where possible.
  • Autumn treatment is preferred where grass is intended for hay or silage, so dead plants have time to rot before cutting and baling.
  • Digging or pulling can leave detached roots that regrow, so remove second-year plants before flowering and wear protective clothing, rubber or neoprene gloves, and a pollen mask when plants are flowering.
  • Maintain dense, vigorous pasture through appropriate fertiliser and grazing management to reduce opportunities for seedlings to establish.

Hygiene and washdown

  • Clean vehicles and machinery to avoid moving seeds in mud or soil, and avoid spreading root or crown fragments.
  • Ragwort seeds can also be spread in stock feed, so take care not to move contaminated feed.
  • 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: Regional priority in 1 of 11 regions. Regional priority weed in Riverina. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Regionally prohibited / regionally controlled / restricted weed (varies by region). Where it is regionally prohibited, landowners must take all reasonable steps to eradicate it on their land. Where it is regionally controlled, landowners must take all reasonable steps to prevent its growth and spread on their land. Where it is a restricted weed, trade in it (including the plant, its seed or contaminated material) is prohibited.
  • 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, C2), 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. C2 Eradication: present in limited areas and targeted for eradication. It must not be brought into WA (prohibited organism).
  • 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
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania

Sources