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. 

Identification:

• 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

Habitat:

Common Ragwort is found growing in waste ground, roadsides and pastures.

Reproduction:

• 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

Impacts:

• 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

Treatment:

• 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. 

Distribution:

Distribution of Ragwort in Ireland

 National Biodiversity Data Centre, Ireland, Common Ragwort (Senecio jacobaea), image, accessed 19 January 2023, <https://maps.biodiversityireland.ie/Species/TerrestrialDistributionMapPrintSize/29601>