Photo Credit: Steve Dewey, Utah State University, Bugwood.org
Photo Credit: Jan Samanek, Phytosanitary Administration, Bugwood.org
Also known as: common tansy, golden-buttons, garden tansy
Originally brought to North America from Eurasia in the 1600s, common tansy has slowly spread westward over time. It primarily infects pastures and displaces desirable forage plants.
|Life Cycle:||Perennial (life cycle lasts more than one year)|
|Early Detection and Rapid Response species:||No|
|Height:||1 – 5 feet (.3 – 1.5 meters)|
|Leaf Description:||Fern-like foliage with narrow, toothed leaves. They become smaller towards the top of the stalk and produce a strong aroma when crushed.|
|Fruit & Flower Description:||Flowers are yellow and button-like and arranged in flat-topped clusters. It produces lightweight seeds that can be dispersed by wind, water, and equipment.|
|Bloom Time:||June to August|
- Generally found along roadsides, streambanks, and in pastures.
- It grows in a variety of soil types and light conditions.
- Highly invasive and can severely reduce pasture capacity and desirable forage.
- It is reportedly poisonous to livestock, though it is seldom grazed due to its strong odor.
What you can do about it:
- Prevention is the best control – make sure to remove all seeds from personal gear, equipment, and animals before leaving an infested area.
- Mowing before the plant produces flowers and seeds is beneficial. Repeated mowing is required to keep plants from re-sprouting.
- Small infestations can be hand pulled or dug up. This is easiest and most effective in the spring after a rain when the ground is damp and before the plant has produced seeds.
Common tansy is often confused with a couple other invasive species: St. John’s wort (Hypericum perforatum) and tansy ragwort (Jacobaea vulgaris). Unlike tansy ragwort and St. Johns wort, common tansy flowerheads are button-like and does not have petals.
Noxious Weed Listing:
|State of Oregon:||Not listed|
|State of Washington:||Class B|
Download the Common Tansy Best Management Practices Factsheet