Welcome to the Thurston County Noxious Weed Control Website!

Contact Information

11834 Tilley Rd. S.
Olympia, WA 98512

Location Map

(360) 786-5576



Public Works

Ramiro Chavez, Department Director and liaison to the Board of County Commissioners

Thurston County Noxious Weed Control Board Members:

Gene Little, Chair
Martin Casey, Vice Chair
Jeff Grimm
Patricia McCann
Dorothy Saunders

Noxious Weed Control Staff

Rick Johnson, Coordinator
Mary Jo Seery, Lead Weed Technician
Dan Reynoldson, Weed Technician
Angela Celestine, Office Assistant


  Cortaderia seloana, also known as “Pampas grass”, has been a widely planted favorite in the Northwest for many years.  Native to Brazil , Argentina and Chile, established plants are a common sight in neighborhood landscapes, its feathery, distinctive plumes reaching up to 20 feet in height.  Until recent years Pampas grass seemed to be well-behaved in the Northwest, as they were almost exclusively female plants, grown from root divisions for their superior ornamental qualities.  Now there are both male and female plants sold. Seed packets have been found offered for sale at local garden retail outlets. Both Pampas grass and Jubata grass have escaped and infested large areas in some places in the United States, particularly California, smothering native plants and creating serious fire hazards due to the large amount of dead, dry material that is produced by plants every year.

On October 9, 2013 an escaped population of Pampas grass was discovered off West Bay Drive located on private property.With permission from the property owner, photos above were taken at this site. With the use of a Trimble GPS unit we logged 484 escaped plants on this property. Many seedlings as well as first year plants were found. Some young plants had plumes only 3’ high. For more information and control options, please click here.


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 of 86 designated by the State of Washington. The remaining 46 species have not yet been found in Thurston County, but are targeted annually through early detection surveys. 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.

Agency staff are surveying for the remaining 46 species not yet known to exist in Thurston County. This preventative effort to find species while they are limited,  prevents them from becoming widespread. Prevention is the most effective control strategy.

Nuisance Weeds

In addition to the species listed on the County noxious weed list, there are weeds of special concern because of their aggressive and invasive natures. 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). 

Thurston County Noxious Weeds Map

Thurston County Weeds Map

Click the image above to go to the Noxious Weeds Map on the Thurston County Geodata web site. Use this map to see which known noxious weed species are in your neighborhood. Here's how:

  • Select the search tab to find your property either by address or parcel number.
  • Select the layers tab, under miscellaneous on the list of possible layers, check the box next to the noxious weed layer to turn on.
  • Known noxious weed species symbols will then appear, use the legend tab to identify symbols of the species of noxious weeds that are depicted.

Contact Us

Address questions or comments to: tcweeds@co.thurston.wa.us

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