05/28/2026
Think you’re looking at tansy that needs to be reported? Take a closer look. There’s a native species that can be confused with tansy. Before you report common tansy or tansy ragwort, both Class B noxious w**ds, try to confirm that you’re not looking at native common yarrow.
Class B Noxious Weeds
Common tansy
🌱 Stem: Brown to reddish brown
🌱 Leaves: Divided into 4–13 pairs of finely toothed leaflets
🌱 Flowers: Yellow, button like flower heads
Tansy ragwort
🌼 Growth: Usually reach 2–4 feet tall, but can grow up to 6 feet
🌼 Leaves: Deep green, ruffled or lobed, often described as kale like, up to 8 inches long
🌼 Flowers: Bright yellow, daisy like blooms arranged in flat clusters
🌼 Seeds: Each plant can produce up to 150,000 seeds per year, which can remain viable in soil for 10+ years and spread easily by wind
Native Plant: Common Yarrow
🌱 Leaves: Soft, finely dissected, and feathery
🌱 Flowers: Dense clusters of many small blooms that can be white, pink, red, or yellow
🌱 Notes: Can appear like a w**d, but is also used in gardens for pollinators!
If you suspect that you have found a noxious w**d, please report it at clark.wa.gov/public-works/report-noxious-w**d-concern.
For more information, visit nwcb.wa.gov/w**ds.