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  • Grows 0.2-1.2 m tall

  • Introduced from Europe 

  • All parts of the plant contain chemicals that form a toxic compound when they enter the liver


Tansy ragwort
(Senecio jacobaea)

Quick Identification

  • Small, yellow, daisy-like flowers

  • A biennial to short-lived perennial which forms a rosette in its first year

  • Deeply lobed leaves

Toxic to animal and people causing liver issues, photosensitivity, and even death.  It is often spread in hay posing a danger to livestock.  In addition, it can reduce forage by up to 50 percent.

Manual control can be effective if entire plant and root system is removed.  Wear protective gear.  Cutting and mowing are not effective as the plant will regrow.  Effective herbicides are available but some herbicides can make the plant more palatable to animal which can increase the risk of poisoning.

Clusters of yellow, daisy-like flowers.  Unlike common tansy, tansy ragwort flowers have a ring of 10 to 15 petals around the yellow to orange center.

Leaves & Stems
Leaves are roughly lobed and dark green.  Stems are purple to green and branch in the upper part of the stock.  Plant has fine hairs.

Preferred Habitat
Prefers overgrazed pastures, trails and road sides, and disturbed areas.

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A short, whitish taproot with spreading fibrous roots.

Reproduction & Dispersal
Primarily reproduced by seed but can also regrow or propagate from damaged or severed roots. Is often spread in hay or when soil is moved.


Each plant an produce 15,000 seeds each year which geminate in fall or spring to form rosettes.  Seeds remain viable for up to 15 years depending on conditions.  Seeds are spread by wind or when hay or soil is moved.

Interesting Facts
Native to Europe, Asia, and Siberia, it is though to traveled to Canada in ship ballast water or as a medicinal herb.

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