Common Tansy (Tanacetum vulgare)

Gallery:

Common tansy flowers

Common tansy plant

Common tansy leaf

Common names:

common tansy

Scientific Name:

Tanacetum vulgare (syns. Chrysanthemum vulgare, Tanacetum boreale)

Description:

Common tansy is an aromatic perennial with rhizomes, reaching 1 to 5 feet tall, with fern like foliage and yellow button-like flowers. Flowerheads are numerous, button-like and yellow. They are 1/4 to 1/2 inches across in flat-topped dense clusters. Flowerheads composed of all disk flowers and are absent of ray flowers. Leaves are alternate and pinnately compound (leaflets arranged on both sides of a common stalk). They are deeply divided into numerous, narrow, toothed segments. Leaves become smaller towards the top of the stalk and are strongly aromatic when crushed.

Life cycle:

Perennial

Height of mature plants

1-5 feet

Flower color:

Yellow

Bloom time:

June through August

Look-a-likes:

Common St. Johnswort (Hypericum perforatum) and tansy ragwort (Senecio jacobaea) may be mistaken for common tansy. Common St. Johnswort flowers have 5 petals per flower while common tansy does not have any petals (ray flowers) and and tansy ragwort has on average of 13 ‘petals’ (ray flowers).

Habitat:

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Impacts:

Common tansy is reported to be poisonous to livestock, though it is seldom grazed due to its strong odor. It displaces forage plants, reduces wildlife habitat and species diversity.