Beware Of Giant Hogweed, King County Warns

KING COUNTY, WA —King County officials are asking residents to be on the lookout for a noxious weed after recent sightings in urban areas. Giant hogweed, a toxic perennial classified as a Class A noxious weed, can grow up to 15 feet tall and is often found in cities, yards and empty lots, officials said. The plants produce sap that can cause severe blisters and scarring if it comes into contact with a person's skin.

An oversized member of the parsley family, giant hogweed blooms from May through July and has proven effective at spreading in a variety of environments where humans may encounter it. Due to the plant's appearance, it can sometimes be mistaken for cow parsnip.

Officials write:

"Giant hogweed is originally from Asia and was introduced as an ornamental. Spreading by seed, giant hogweed has escaped into numerous backyards, ravines, parks, abandoned lots, streams, woods, and roadsides. It can crowd out other plants and take over natural areas, especially in moist areas such as streamsides. Somewhat shade tolerant, giant hogweed can also thrive in full sun and has been known to even invade healthy turf. A public health hazard, hogweed's clear, watery sap has toxins that cause photo-dermatitis. Skin contact followed by exposure to sunlight produces painful, burning blisters that may develop into purplish or blackened scars."

Because of giant hogweed's noxious nature, the law requires property owners to deal with the plant if it's growing on their land. Since handling the plant poses a risk of injury, officials recommend people contact the noxious weed program first to positively identify the weed and hear recommendations for safe handling.

Anyone who thinks they spot the noxious weed, either on their property or out in the wild, is also encouraged to report the sighting online to help the county track potential infestations and take action. Residents can also find an updated map of giant hogweed and other noxious plants reported across King County online. The map shows reports of giant hogweed especially concentrated around Seattle and Renton.

Residents can report sightings using an online form and reach out to the Noxious Weed Control Program at 206-477-9333. More photos and information about how to identify giant hogweed are posted on the King County website.