Common Ragwort

Jacobea vulgaris, Buachalán buidhe

Ragwort, also known as ragweed and buachalán buidhe, is a member of the Asteraceae family. Ragwort is a biennial plant. It thrives in free draining soils. Ragwort is listed as a noxious weed under the Noxious Weed Act 1936.

Common Ragwort


National Biodiversity Data Centre, Ireland, Common Ragwort (Senecio jacobaea), image, accessed 19 January 2023)

Species Recorded: 

Jacobea vulgaris, Buachalán buidhe

Invasiveness rating:





  • In first year of growth a rosette of leaves is present, in the second year, a stem of around 130cm grows bearing flowers.
  • Flat-topped clusters of yellow flowers in July to October
  • Leaves are dark green and pinnatifid


  • Each plant produces around 50,000 – 200,000 seeds or achenes
  • Achenes have simple hairs which allows for animal, water and wind dispersal
  • Seeds can remain viable for up to 20 years depending on conditions
  • The plant can regenerate from root fragments


  • Ragwort is highly poisonous to cattle, deer, horses, chickens, pigs, and goats.
  • Ragwort is not as poisonous for sheep but can still affect the animal
  • The toxic alkaloids, Jacobine, Jacodine, Jaconine are what makes Ragwort poisonous
  • As the plant is unpalatable, the plant won’t be eaten by livestock unless grass is scarce.
  • Ragwort in silage is dangerous as it still remains poisonous


  • Physical: Ragwort can be pulled by hand when the ground is soft and before seed has set in early Summer. Uprooted plants should be destroyed. This should happen for 2 years. Cutting before seed has set in mid-June will reduce the spread of the plant. This should be carried out in tangent with pulling.
  • Chemical: Ragwort can also be treated by chemical control using a 2,4 D containing herbicide and applied to rosettes in April-May or mid-August to mid-October, and from March-May for adult plants.
  • Biological: The Cinnabar moth is a control agent for Common Ragwort. It is native in Ireland but has been introduced into New Zealand and the US as a control agent for ragwort. Cinnabar moth larvae are specialized to feed on the ragwort. The extent of the damage depends on the number of caterpillars. This control is limited.

More photos: 

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