Photo Credit: Steve Dewey, Utah State University, Bugwood.org
Photo Credit: Jan Samanek, Phytosanitary Administration, Bugwood.org
Photo credit: (c) Bruce N. Newhouse, courtesy of Oregonflora
Photo credit: (c) Steven Katovich, Bugwood.org
Also known as: golden-buttons, garden tansy
Originally brought to North America from Eurasia in the 1600s, common tansy has slowly spread westward. It is distasteful to livestock and displaces desirable forage plants in pastures.
|Perennial (life cycle lasts more than one year)
|Early Detection and Rapid Response species:
|Up to 5 feet (1.5 meters) tall
|Fern-like leaves have 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 is a prolific seeder. Each plant produces around 2,500 seeds annually. Its seeds can be dispersed by wind, water, and equipment.
|June to August
- It is found along roads, streambanks, and in pastures and abandoned fields.
- It is extremely hardy and grows in a variety of soil types and light conditions but thrives in sunny conditions.
- Tansy stands are dense and outcompete native plants, crops, and forage for livestock.
- It is poisonous to humans, cattle, horses, and chickens when consumed in large quantities. It is seldom grazed by livestock 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.
- 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.
- Dispose of all plant materials in a tied plastic bag and throw it away in the trash – not the yard debris or home compost.
- Mowing before the plant produces flowers and seeds is beneficial. Repeated mowing is required to keep plants from re-sprouting.
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’s flowers are button-like and do not have petals.
Noxious Weed Listing:
|State of Oregon:
|State of Washington:
Download the Common Tansy Best Management Practices Factsheet