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.

Perennial

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).

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 banks effectively. Common Tansy will also spread by creeping roots.

Widespread throughout the region except for the Chilcotin, but in scattered locations.