Tansy Ragwort (Jacobaea vulgaris/Senecio jacobaea)

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Tansy ragwort is a biennial plant or short-lived perennial in the sunflower Family (Asteraceae). Erect purplish-red stems grow to 1.5 m tall. Leaves grow up the coarse stem and are 2 or 3 times pinnately lobed. The daisy-like bright yellow flower heads have disk and ray flowers up to 0.5 inch long. Seeds are easily transported by wind, water and animals. One ragwort plant can produce in excess of 150,000 seeds. Seeds can lie dormant on the soil surface for 4 to 5 years or over 20 years if buried. The plant has deep tap roots.

Key Identifiers

  • Young plants have basal rosette of ruffled leaves
  • Leaves are dark green on top, whitish-green underneath, and have deeply cut, blunt-toothed lobes with a ragged/ruffled appearance
  • Flat-topped flower head clusters, composed of yellow, daisy-like flowers, with (usually) 13 petals
  • Flowers have both disc & ray florets
  • Seed has white pappus allowing wind dispersal
Location in Canada
Tansy ragwort known to be in Nova Scotia, New Brunswick, Prince Edward Island, Newfoundland and British Columbia, with sparse collections from Ontario and Quebec.

Richard Old, XID Services, Inc., Bugwood.org
Resources Similar species
Common Tansy (Tanacetum vulgare) Flowers are only disc florets and lack “ruffled” leaves.
Alberta Invasive Plants Council - Common Tansy
Desert Ragwort (Senecio eremophilus) Leaves lack “ruffed” appearance. Saskatchewan Wildflowers - Desert Ragwort
Marsh Ragwort (Senecio congestus) Stems are hairy and leaves lack “ruffed” appearance.
hAlaska Wildflowers - Marsh Ragwort

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For more information about the content of this document, contact Chris Neeser.
This document is maintained by Shelley Barkley.
This information published to the web on April 10, 2012.
Last Reviewed/Revised on August 21, 2018.