Field Guide   pic  Weed Management   pic  Tansy Mustard

Tansy Mustard (Descurainia pinnata)

Crop Impacts: Pasture

Tansy Mustard 1

About Tansy Mustard:

Tansy Mustard is a cool season, annual weed that can be found throughout North America. When consumed in large amounts it can be toxic to animals, most commonly cattle. There are a few signs you can look out for if your cattle have consumed a lot of Tansy Mustard, these can include blindness and a paralyzed tongue.

Family: Mustard family (Brassicaceae)

Tansy Mustard 2 Tansy Mustard 3

Tansy Mustard Scouting and Prevention:

As a young plant, Tansy Mustard has low rosette and basal shaped leaves that can span from 4 to 8 inches across. As the plant matures, it grows about 2 feet tall with a single wavy stem with many leaves and is covered with small gray hairs. The leaves of this plant are placed alternating one another with each leaf divided into many small, narrow segments which can grow up to 8 inches long. The Tansy Mustard weed produces whitish to yellow flowers, with 4 petals per flower, which grow in long clusters near the end of the stem. These flowers bloom from February to May.

Common locations

  • - Dry or sandy soil
  • - Fields


Prevention of Tansy Mustard is less expensive and less time-consuming then trying to control it. Make sure when you seed a new area you do so with certified weed-free seeds. If there is an infested area on your property, be sure to drive around instead of through it. Make sure to give all equipment that has been in infested fields a good clean to make sure no seeds are transferred.

Tansy Mustard Control:

Cultural Control

An effective way to control the population of Tansy Mustard is by cultivation or manually removing it by hand before the seeds develop. The best time to physically remove Tansy Mustard is when the plant is young and the soil is wet. During this time you will have an easier time removing the entire root system. Mowing is another option for older plants that are in the bud to bloom stage to reduce the seed production. Continuous control methods used over several growing seasons will eventually exhaust the seed bank of Tansy Mustard.

Chemical Control

Trying to control older and larger plants is much more difficult and time consuming; therefore, timely application is critical. Herbicides will be ineffective if applied when the plant is under stress. The herbicides will have more effect right before or right after rain due to the fact that the roots of the plants are taking in water at the time, which in turn means they will be taking in the herbicide as well.

Latin / Alternative Tansy Mustard names:

  • - Descurainia pinnata (Walt.) Britt.
  • - Green tansymustard
  • - Tansymustard
  • - Western tansy mustard

Additional Tansy Mustard Resources