Tansy Ragwort is a noxious weed that is poisonous to almost all livestock, especially horses and cattle, (humans too) when it is ingested. Toxins within the plant cause irreversible liver damage and death. All parts of the plant are poisonous, with flowers being most toxic, followed by leaves, roots, and stems. Tansy will remain toxic when cut and dried in hay or when mowed in the field to prevent its flowering, and the chopped plant material is left to dry.

Tansy Ragwort is easily seen right now, as July and August are the months it blooms profusely. It is a tall plant, from about 1 ½’ to 4’ in height. It has large, bright yellow flower clusters at the top of the stem, and a sort of ruffled, dark, olive-green foliage growing at the base with some ruffled leaves along its stem too. It can be found growing in and along ditches, along roadways and in highway medians. Tansy will grow in overgrazed or unkempt fields and in areas disturbed by construction, logging, and even fire.

Once Tansy begins to bloom, herbicide treatments become ineffective and are a waste of time and material. Herbicides should be applied to Tansy with labeled products in spring when the plant is in its rosette stage of development and is actively growing. Fall treatments can help but one must wait until some fall rain brings the plant out of summer dormancy to get some control. New seedlings that emerge in fall can be killed easily at this time too. Mowing Tansy down can help with its control when done properly but be cautious. Mow too early, and the plant may bolt and bloom anyway; mow too late, and one can aid the spread of the Tansy seed and expand the plants range. Those who choose to mow must not graze livestock in the areas that received mowing. The animals could easily consume the chopped, dry Tansy with their forage.

The only effective control of blooming Tansy is to pull it up, root and all by hand, taking care to get the whole taproot. A new plant can grow from even a very small piece of root left behind. Wear gloves, long pants and sleeves when pulling or handling tansy in any way. Put all plant material in poly garbage bags and dispose of it in the trash. Do not compost this plant material! Another option to control Tansy would be to cut off and remove all the plants flower heads before they develop seed. Dispose of the flower heads in the same manner as the whole plant. Then, plan on applying a Fall herbicide treatment to these plants. Apply the appropriate herbicide after fall rains have stimulated a green up of the plant rosette and any new Tansy seed that has germinated. Once the rain has stimulated this new growth, the spray treatment can be applied effectively. Herbicides containing 2,4-D and Dicamba together work very well on Tansy Ragwort and are economical.

Go to the Oregon State University Extension website for more information on Tansy Ragwort and its control – –   Stop in at Burns Feed Store for gloves, rubber boots, spray equipment, herbicide, and helpful advice to aid in stopping a Tansy Ragwort infestation on your land.