A European introduced garden plant that escaped cultivation, Tansy earned its vulgare (common or ordinary) label for its weedy nature. The plant often overtakes large tracts of moist disturbed soils.
Introduced aromatic , 16-72" tall. Numerous yellow, button-like disk flowers, formed into flat-topped branching clusters at end of stems. Leaves are , fern-like with divided leaves. Leaf axis is . Small pitted on leaves produce strong odor. Stems are often purple-red. Browned flowers persist into fall and early winter. Seeds are yellow-brown capped with a .