Description: Common tansy was introduced to North America from Europe as a garden herb and is found across the continent as far north as the Northwest Territories (Royer and Dickinson 1999). It is a perennial forb with rhizomatous roots and clusters of bright yellow compound flowers that can grow to 1.5 m height.
Habitat & Impacts: Common tansy requires open habitats in fertile soil usually becoming established on disturbed ground. This species can spread into adjacent undisturbed areas once established. It is especially prone to infesting riparian areas where chemical control is not possible. This species can have significant impacts in riparian areas, by reducing native vegetation, affecting stream bank stability and reducing forage quantity and quality for livestock and wildlife. Common tansy is unpalatable to most livestock and may be mildly toxic in some cases (Royer and Dickinson 1999).
Method of Spread: Seed production is large with each plant producing up to 50,000 seeds. Seeds may be dispersed by wind and water but are not dispersed far from the parent plant. The seeds of common tansy do not appear to seed bank effectively. Common Tansy will also spread by creeping roots.
Location: Widespread throughout the region except the Chilcotin, but in scattered locations.
Mechanical Control: Mowing prior to seed set can eliminate seed production but must be repeated over a number of years to diminish establishment. Hand pulling with removal of the tap root can be effective.
Chemical Control: Herbicide control of common tansy is very effective and a single treatment may eliminate an infestation and a wide range of herbicides appear to be effective. Common tansy is relatively easy to control chemically.
Biological Control: There are no biocontrol agents available in British Columbia.
CCCIPC Priority & Treatment Strategy: Priority 1 (new invader) in Chilcotin and the Central Coast, all other areas Priority 2 (containment). Inventory is incomplete for this region and needs to be improved. The management strategy may need to be revised once better inventory information is available.
Local Level - repeated mowing and hand pulling, or herbicide
Landscape Level - herbicide
Common Tansy leaf
Common Tansy plant in flower
Common Tansy infestation
Invasive species profile taken from the Cariboo Chilcotin Coast Invasive Plant Committee Invasive Plant Regional Strategic Plan
Page last modified: March 15, 2017 09:36:29 PDT