Where does it grow?

Most common along roadsides, other rights-of-way, vacant lots, streams and rivers.

What is the distribution in Washington State?

• Giant Hogweed has been documented in Thurston, King, Kitsap, Mason, Island and Clark counties.
• If you think you may have seen this weed, please contact your county weed coordinator or us at noxiousweeds@agr.wa.gov.

• Distribution map not available at this time.

How do I control it?

General control methods: Always wear protective clothing and avoid getting sap on skin, the sap that causes the burning is contained in all portions of the plant.

Cultural: Plants may be dug-out but care should be taken to remove much of the root stalk this can be difficult.

Herbicide: Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator.

Mechanical: Mowing serves only to stimulate budding on the perennating root stalk, but might be successfull if done consistently and persistently enough to starve the rootstalk.

Biological: Cattle and pigs are cited as possible biocontrol agents. Both eat giant hogweed without apparent harm.

Are there plants that may be confused with Giant Hogweed?

Cow Parsnip Heracleum lanatum, is a native plant in Washington and except for it's size, has a similar appearance to Giant Hogweed. A field guide of Pacific Northwest wildflowers can help you with identification, or you can contact the WA Native Plant Society. Your county noxious weed coordinator  can also help with identification. Click on photos below to enlarge.

Cow Parsnip leaf            Cow Parsnip plant

For more information