Bumper crop of tansy ragwort creating headaches for county workers and homeowners alike

If it seems like there’s more tansy ragwort in your neighborhood this year, you aren’t alone. Tansy ragwort plants are larger and more numerous just about everywhere in King County. County weed specialists report seeing tansy ragwort in places it hasn’t been in over 10 years. And some of the plants have been enormous!

Tansy ragwort can grow taller than a person if conditions are just right.

We had a perfect storm of weather conditions this winter and spring that has allowed tansy ragwort to thrive. A mild winter meant more seedlings and rosettes survived the winter, a hot spring got everything growing early, and then spring and summer rains have given them just what they needed to grow huge and healthy.

In order to fight back and avoid losing all the progress we’ve made in the past, weed specialists are urging everyone to pull up the plants, roots and all or at least cut off the flowers and bag them for disposal. It’s hard to pull plants up when the soil is hard, but even removing the flowering stems will help reduce the spread of the plant.

County worker cutting off the heads of tansy ragwort to keep the plants from going to seed. Photo by Sasha Shaw.

County residents can call our program to receive a voucher to cover the cost of noxious weed disposal at county transfer stations. Call 206-477-9333 or email us at noxious.weeds@kingcounty.gov and let us know where to mail the voucher. We would rather see these toxic weeds in the garbage than to allow them to spread further. You can also report infestations of tansy ragwort on our online form. Let’s work together to keep this toxic plant from taking over!

Tansy ragwort in a field on Vashon Island. Photo by Sasha Shaw.


  1. Hi, haven’t seen large infestations but when I drive in unincorporated king county, I see tansy ragwort a lot. May Valley road has areas where the weeds aren’t pulled along the road, especially around Squak Mtn State park.

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