Welcome to the Thurston County Noxious Weed Control Website!

Thurston County facilities are now open to the public with restrictions, including maintaining physical distancing of at least six feet at all times and, per the Washington State Secretary of Health’s face covering order , wearing a cloth face covering or mask. If you come to county facilities, please be prepared for potentially long wait times or lines due to distancing guidelines. We continue to encourage residents to access county services online, by phone, by email, or through the use of drop boxes located outside of county buildings.
The availability of remote services vary by office and department.
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Contact Information

9605 Tilley RD S
Olympia, WA 98512

(360) 786-5576



Public Works

Jennifer Walker
Department Director and liaison to the Board of County Commissioners

Tim Wilson
Water Resources Manager

Thurston County Noxious Weed Control Board Members:

Carol Piening, Chair

Fran Sant, Vice Chair

Paul Thomsen

David Mills

WSU Thurston County Extension

Stephen Bramwell,
WSU Extension Director

Thurston County Lake Management Districts:

Lake Lawrence

Long Lake


Our mission is to protect the citizens, the natural resources, and the agricultural resources of the County from the degrading impact of invasive, noxious weeds.


Noxious weeds threaten public health, the environment, wildlife habitat, native plants, agriculture areas, and recreational areas.

Thurston County Noxious Weed Control is monitoring for 40 species of noxious weeds which are targeted for control out of a list designated by the State of Washington, which are known to exist in Thurston County. Species that have not yet been found in Thurston County, are targeted annually through early detection surveys.This preventative effort to find species while they are limited prevents them from becoming widespread. Prevention is the most effective control strategy. All species of noxious weeds are non-native.

A risk assessment is used in prioritizing the weed list. To view our rationale, go to the Risk Assessment Chart. To see photographs of those species designated for control in Thurston County, go to the Noxious Weed List.

Species of Concern

In addition to the species listed on the County noxious weed list, six species pose a significant threat due to their invasive traits: spartina, kudzu, garlic mustard, hydrilla, water primrose and flowering rush. These species are not yet found in Thurston County.

In addition to the species listed above, there are weeds of special concern because of their aggressive and invasive natures.These species are already known to be widespread in Thurston county. These include:

Evergreen blackberry (Rubus laciniatus), Himalayan blackberry (Rubus armeniacus), Eurasian watermilfoil (Myriophyllum spicatum), Policeman’s Helmet (Impatiens glandulifera), Canada thistle (Cirsium arvense), Scotch broom (Cytisus scoparius), yellow nutsedge (Cyperus esculentus), and the invasive cultivars of English Ivy: Hibernica” (Hedera hibernica), “Baltica” (Hedera helix), “Pittsburg” (Hedera helix) and “Star” (Hedera helix). 

Disposal of Noxious Weeds

  • Some problem weeds such as Knotweed, Scotch broom, blackberry and English Ivy are not on Thurston County's list for free disposal, but are of concern to citizens.Click here to find out what do to with other bad weeds.

Contact Us

If you have a question or problem concerning noxious weeds,and ask to speak to a Noxious Weed Specialist. For inquiries about a Lakes Management District (LMD) - Long Lake or Lawrence Lake, ask to speak to our Aquatic Resource Specialist.

By Phone: 360-786-5576

By Email: tcweeds@co.thurston.wa.us