County sounding the alarm as harmful weeds begin to grow

  • Written by King County Department of Natural Resources and Parks
While early spring has the welcome blooms of cherry trees, tulips and daffodils, it’s also the season when noxious weeds, such as giant hogweed, poison-hemlock and garlic mustard have a growth spurt.

King County noxious weed experts are alerting homeowners and gardeners to be on the lookout for these nasty invaders, which can be a threat to people, animals and entire ecosystems.

Steven Burke, King County Noxious Weed Program manager, said giant hogweed, poison-hemlock and garlic mustard are easily spotted in the spring and should be dealt with as soon as possible.

• Poison-hemlock is acutely toxic if eaten by people or animals. It closely resembles a carrot plant when it is young and can be confused with fennel and anise when it is flowering or in seed.

• Giant hogweed can cause burns and blisters on the skin.  It shows up in urban alleys and ravines where it has spread from ornamental plantings.

• Garlic mustard is edible for people but rapidly takes over in forests and stream banks, where it out-competes native plants and reduces habitat for local fauna.

• Additionally, horse and cattle owners are also being urged to watch for tansy ragwort, which can cause deadly liver poisoning in animals.

Young tansy ragwort plants can be found this month and will be easy to spot later in the spring as they being to grow flowering stems.

The county’s noxious weed program is available to help residents learn to identify and control these and other harmful noxious weeds. Weed specialists will be on hand at several community events this spring and summer.

Details and the full schedule of noxious weed information tables for the year can be found on the county’s website. Community groups can schedule a presentation on noxious weeds or an information booth at their event by contacting education specialist Sasha Shaw, at (206) 296-0290, or This email address is being protected from spambots. You need JavaScript enabled to view it..

Noxious weeds are non-native plants that impact natural resources, agriculture, and human health in King County or in other counties in Washington.

The list of species that property owners and public agencies are required or advised to control in King County is found on the County’s noxious weed website.

Information on noxious weeds, including the King County weed list and the Washington noxious weed law, can be found online at

For more information on the King County Noxious Weed Board and Noxious Weed Program, call or email Burke at (206) 296-0290 or This email address is being protected from spambots. You need JavaScript enabled to view it..

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