Invasive Species Council of British Columbia
Invasive Plant

Common tansy

Tanacetum vulgare
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Toxic to humans and livestock

About This Species

Common tansy (Bitter buttons, Cow bitter, Golden buttons) is a herbaceous plant that was introduced to North America in the 1600s for medicinal purposes. It is native to Europe and Asia. It spreads via roots and seeds that can remain viable for up to 25 years.  

Tansy is often found growing in sunny, disturbed areas such as roadsides or pastures where it can displace native vegetation. Infestations in rangeland can be toxic to livestock, and it’s reported that dairy cattle consuming the leaves often have unpleasant tasting milk. Common tansy is designated as a Regional Noxious Weed by the BC Weed Control Act. 

How to Identify

Common tansy plants range from 0.4–1.5 m tall and can grow in thick infestation. 

Flowers are bright yellow, flat-topped, round and grow in clusters. 

Leaves are dark green, and its leaves fern-like and divided with sharp edges. Each leaflet is serrated.  

Take Action

Prevention is the best approach.



Learn about best practices

A few non-invasive alternatives to plant instead of Common tansy include:

  • Yarrow (Achillea millefolium)
  • Tall coneflower (Rudbeckia laciniata)
  • Summer sunflower (Heliopsis helianthiodes)
  • Morden Eldorado garden mum (Chrysanthemum x morifolium ‘Morden Eldorado’)
  • Flat-top goldentop (Euthamia (Solidago) gramnifolia)


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