Poison hemlock removal planned across Shoreline

A sign warns walkers of a patch of poison hemlock growing in a thicket of noxious weeds near the stairs at Richmond Beach Saltwater Park while stair climbers get in some steps before sunset. Photo by Oliver Moffat

Before sunset on Thursday evening, stair climbers huffed and puffed past a sign near the top of Richmond Beach Saltwater Park warning of the dangers of nearby poison hemlock growing amongst an uncontrolled patch of Himalayan blackberries. 

Across town at James Keough Park dogs and their owners enjoyed an evening stroll while young poison hemlock shoots grew in a patch of weed cherry trees.

Starting next week, the city will be using herbicide to remove the highly toxic weed from locations around the city including the Richmond Beach and Innis Arden neighborhoods and at Richmond Beach Saltwater Park and James Keough Park.

• Richmond Beach Saltwater Park – several locations
• James Keough Park – the southwest part of the park
• Richmond Beach Dr. NW between NW 195th Street and NW 196th Place
• 15th Avenue NW between 14th Avenue NW and NW 175th Street

Young poison hemlock sprouts near a stand of noxious weed cherry at James Keough Park. Photo by Oliver Moffat

According to the King County Noxious Weed Control Program, poison hemlock is highly toxic and, if ingested, even small amounts can kill people and animals. It’s widespread across the region and thrives in open sunny areas like vacant lots and along roadsides where other noxious weeds flourish.

Because of its extreme toxicity and aggressiveness, the state has designated this plant a Class B Noxious Weed - meaning that governments are required to eradicate it by any means necessary. Including the use of herbicide.

Residents should be on the lookout for poison hemlock which can grow to 6-10 feet tall and produce tiny, white, 5-petaled flowers in late spring. The plants have a resemblance to carrot tops this time of year. 

Flowering poisonous hemlock may be confused wild carrot (aka Queen Anne's Lace) which is also a noxious weed but non-toxic.

Shoreline seeks to “reduce and/or eliminate use of pesticides in the city” under its pest management policy. For example, favoring “mechanical control” of pests including “hand pulling” of noxious weeds in public parks. 

This backbreaking work is primarily performed by volunteers with the Green Shoreline Partnership in parks across the city.

On city right-of-ways, the city uses a hot foam herbicide-free solution to address weeds which kills weeds along with beneficial fungi, flora and fauna in the soil.

The city attempted to remove the poison hemlock in recent years without herbicide, pulling the plants out by hand. But that technique failed.

But when it comes to a weed as aggressive and dangerous as poisonous hemlock, the city will use herbicides to eradicate it.

With more than 400 acres of park land and open spaces in Shoreline, the city’s Green Shoreline 20-Year Forest Management Plan identified 240 acres of forest in 23 parks in need of noxious weed removal and restoration by 2039 - a pace of roughly 9.6 acres per year. 

Yet in the six years since its founding in 2017, volunteers working with the Green Shoreline Partnership have only restored 15 acres in 13 parks - a pace of only 2.5 acres per year, according to Shoreline’s 2023 Urban Forest Strategic Plan.

The county’s website says, “if you suspect poisoning from this plant, call for help immediately because the toxins are fast-acting – for people, call 911 or poison-control at 1-800-222-1222 or for animals, call your veterinarian.”

--By Oliver Moffat