Common tansy is an invasive species. Common tansy is on the Control noxious weed list meaning you must prevent the spread of this plant.
Common tansy is found along roadsides, in gardens and in abandoned farm yards.
South sloping areas are most vulnerable.
Forms dense stands that can reduce desirable forage and pasture capacity, degrade wildlife habitat and interfere with reforestation and landscape restoration efforts.
May be toxic to livestock if consumed.
Common tansy should be reported. The Minnesota Department of Natural Resources provides detailed recommendations for reporting invasive species.
How to identify common tansy
- Common tansy (Tanacetum vulgare) is a perennial herbaceous plant with multiple three to six feet tall, vertical stems giving it a shrub-like appearance.
- Emits a strong odor when crushed.
- A single almost woody, slightly hairy to smooth stem that’s purplish-red at the base.
- The stems have alternate branches that extend toward the top.
- Fern-like appearance with alternate, pinnately divided, toothed edges; two to twelve inches long.
- Leaves become smaller toward the top of the stalk and are strongly aromatic when crushed.
- Bright yellow daisy-like discs up to 1/2" wide, lacking rays; blooms from July through October.
- Resembles a yellow button.
- Develops into a dense flat-topped cluster at plant apex.
- Small, yellowish-brown, dry, five-toothed crowned seeds.
- The seeds are tufted and easily dispersed. They are dispersed by wind and water.
- Each plant is able to produce over 50,000 seeds per year.
- Very fibrous and difficult to remove.
- Root segments easily resprout.
Reviewed in 2019