Tanacetum vulgare (Common Tansy)

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Detailed Information

Flower:

Flowers are in flat clusters up to 4 inches across at the top of the plant, and from stems that arise from the leaf axils near the top of the plant. Individual flowers look like golden yellow buttons, about ¼ inch across. There are no petals (ray flowers), only the center disc flowers. There are from 20 to 200 flowers in a cluster.

Leaves and stem:

Leaves are feathery or fern-like, up to 8 inches long, compound in 4 to 10 pairs of leaflets. Leaflets are hairless, up to 1½ inch long, with sharply toothed lobes and dotted glands. There is a pungent odor when the leaves are crushed. Attachment is alternate. The main stem is ridged and tinged red.

Fruit:

Flower heads turn to dark brown seed heads.

Notes:

Common Tansy is a cultivated plant that escaped into the wild and has become invasive. It is not yet on the noxious weed list for Minnesota, but is on various watch lists. The Ramsey County Cooperative Weed Management Area is focusing on locating all populations of Common Tansy, among other things. If you see this growing somewhere in Ramsey County, please post a comment (below) and let us know where. Thanks in advance for helping thwart this pest.

More photos

• Common Tansy plants, about 30 inches tall

Photos taken at Rice Creek Trail Corridor and Vadnais/Snail Lake Regional Park, Shoreview, MN July-August 2008

Comments

Have you seen this plant in Minnesota, or have any other comments about it?