Ragwort
Botanical Name
Jacobaea vulgaris
Family
Asteraceae (daisy)
Also known as
Senecio jacobaea, tansy ragwort
Where is it originally from?
Europe, West Asia
What does it look like?
Smelly biennial or perennial (occasionally annual) herb (<30-120 cm tall), with a tap root (crown) with numerous fibrous roots extending 30+ cm. Wavy, lobed leaves (5-20 x 4-6 cm) emerge initially from a basal rosette, and stem leaves are deeply cut, clasp the stem, and have no broad terminal lobes. Erect, rigid stems (50-120 cm) are single (multiple in perennial plants), usually purplish and usually branch above the middle. Yellow, daisy-like flowers (<2 cm diameter, Nov-Apr) with golden yellow centres have 11-13 yellow petal-like florets in compact, flat-topped clusters at the ends of stems. Seeds are like thistledown.
Are there any similar species?
Marsh ragwort (Senecio aquaticus) is a very similar exotic that has established in the wild. Also the native groundsel and fireweed Senecio species that are mostly unique to New Zealand are similar. St John’s wort is similar in appearance.
Why is it weedy?
Matures quickly, and produces massive numbers of viable, long-lived, widely dispersed seeds that can rapidly colonise bare spots, light gaps and margins in full or partial light. Tolerates very hot to very cold temperatures, very wet to moderately-dry conditions, most soil types, and a little shade.
How does it spread?
Wind spreads seeds over great distances, and they are also spread by water, soil movement, contaminated machinery, livestock, lime, clothing and hay.
What damage does it do?
Forms dense stands in disturbed and grazed areas, and can (usually temporarily) prevent the establishment of seedlings of native plant species.
Which habitats is it likely to invade?
Invades pasture, disturbed forest and shrubland, short tussockland, fernland, herbfield, wetlands, inshore and offshore islands, river systems, bare land, and coastal areas throughout New Zealand.
What can I do to get rid of it?
1. Physical removal - Hand pull or dig out entire plant - Ensure all root material is removed from site to prevent regrowth.
2. Foliar spray - Spot spray with knapsack. Apply metsulfuron herbicide (600g/kg active ingredient) (0.5g/L) to thoroughly wet all parts of plant. Note: Metsulfuron overspray will kill other (desirable) broadleaf plants and has residual activity in the soil which aids in killing below ground parts. OR apply picloram/triclopyr herbicide (picloram 100g/l and triclopyr 300g/l active ingredient) at a rate of 6ml/L to thoroughly wet all parts of plant. Note: This herbicide is ‘grass friendly’ but overspray will kill other (desirable) broadleaf plants and picloram has residual activity in the soil which may leach through soil and kill other plants. Do not use under and around other (desirable) broadleaf plants. OR Apply Clopyralid herbicide (300g/l active ingredient) at a rate of 12.5ml/L. Note: Clopyralid has residual activity in dead plant material and stock witholding periods may apply. Check the label for details.
For advice on broadcast and winter spray options, please contact your local Regional council or a chemical representative.
3. Biocontrol - For further information regarding ragwort biocontrol please visit: https://www.landcareresearch.co.nz/discover-our-research/managing-invasive-species/weed-biocontrol/projects-agents/biocontrol-projects/ragwort
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and directions for the purchase, use and storage of the product, are followed and adhered to. Do not use over or near water bodies or wetlands and use only as directed on label.
What can I do to stop it coming back?
Ragwort can be left in regenerating bush and shrubland as will disappear as light levels fall.
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