Common Tansy is a horticultural invasive plant that was introduced from Europe and Asia for its medicinal properties.
It is also referred to as Bitter Buttons, Cow Bitter, Mugwort and Golden Buttons.
Common Tansy has “fern-like” leaves that grow about 10-15 centimetres in length on erect stems that can have a reddish purple appearance. The stems are usually smooth and grow anywhere from 50-150 cm tall.
Perhaps the most recognizable feature of this invasive plant is it has small round button-shaped flowers that are yellow and flat topped, and grow in clusters. This plant is said to be aromatic, as it has a smell similar to Camphor, with a hint of Rosemary.
Even though Common Tansy was introduced and widely used for its medicinal properties, the leaves and flowers can be highly toxic if consumed in large quantities. It contains a toxin that can cause hallucinations as well as spasms, brain and liver damage, and in some cases, even death.
To some individuals, it can also cause contact dermatitis. This plant can also be harmful to some livestock.
Often found on stream banks, in disturbed habitats and along roadsides and in pastures, this plant likes full sun and well drained fertile soil. If you have this plant growing in your garden, in your yard, or planted fields, it is important that you deal with it properly to prevent further spread and mitigate potential adverse economic impacts.
Common Tansy grows and reproduces by seeds as well as roots, and can grow new plants from even small root fragments. As such, it is important that you bag any seeds and or plant material in heavy plastic bag and dispose of in the designated invasive plant bin at the Williams Lake, 100 Mile House or Quesnel landfills.
Do not grow, trade or purchase Common Tansy, as there are better alternatives available, including native plant species.
If you have any questions or concerns regarding Common Tansy, or need some assistance in identification or management, contact the Cariboo Regional District’s Invasive Plant Management team at 250-392-3351, or toll free 1-800-665-1636, or visit cariboord.ca.