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Common Tansy

(Tanacetum vulgare)

Common Names

Buttons, golden buttons

Description

Common tansy is a perennial forb that can grow up to five feet in height. Seedlings are petioled, hairy and slightly lobed margins. Later, as the plant matures, leaves take on a fern-like appearance. Leaves can reach ten inches long and up to three inches wide and are a dark green color. Stems grow in clusters, giving the plant a bush-like appearance. They are slightly hairy and  purplish-red closer to the ground. Flowers are button-like, bright yellow to yellow-orange and formed in dense, flat topped clusters on the end of the stems. Flowering occurs from July into October, making it an appealing ornamental for gardeners. The entire plant has a strong odor due to small glands on the leaves that produce scent.  Seeds are grayish-tan in color, ribbed and lack a pappus. Reproduction occurs through a shallow, but extensive root system and by seed.

Key Features

Fern-like leaves; yellow, button-like flower heads, and strong odor associated with the leaves.

Habitat

It grows best in full sun and prefers sites with moist soils. Common tansy grows along roadsides, railroads, stream banks, fields, irrigated pastures, moist valley bottoms, rangeland, gardens and disturbed habitats.

Currently found in the following counties:

Beaverhead, Broadwater,  Carbon, Chouteau, Dawson,Flathead, Gallatin, Granite, Jefferson,  Judith Basin, Lewis & Clark, Lincoln, Madison, Mineral, Missoula, Meagher, Park, Petroleum, Powell, Ravalli, Sanders, Valley, Wheatland

IWM

Interesting Facts

It is reputed that in Pony, Montana, the site of a red light district in the 1800’s, common tansy was used in teas to cause abortions as needed with the ladies of the night. It was also used to prevent or eradicate intestinal worms in people in the middle ages. It is toxic to animals, but poisoning is rare due to the fact that the plant is unpalatable.

Commonly Confused Plants

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Photo credits:

Photo Credits: Brian Ostwald; Mary Ellen (Mel) Harte, , Bugwood.orgSteve Dewey, Utah State University, Bugwood.org; Mary Ellen (Mel) Harte, Bugwood.org; Richard Old, XID Services, Inc., Bugwood.org