Updated September 1, 2021

Now that most of the noxious weeds growing in Spokane County have gone to seed, it is time to think about what you can do this fall to minimize the amount of weeds that return next spring.

Take a look at our Fall Weed Control Booklet to get some ideas on what to do next. 

FallTreatments131 Opens in new window

Listed below are some of the most commonly found Noxious Weeds in Spokane County:

Spotted Knapweed

  • Biennial, Short-Lived Perennial
  • Purple, Pink, sometimes White Flowers

Link to Fact Sheet

Spotted Knapweed 200x173 top ten

Common Bugloss

  • Biennial to Perennial
  • Blue, Purple, Pink or White Flowers

Link to Fact Sheet

Bugloss 200.150 commonly found

Rush Skeletonweed

  • Perennial
  • Small, Bright Yellow Flowers

Link to Fact Sheet


Canada Thistle

  • Perennial
  • Pink to Purple, occasionally White Flowers

Link to Fact Sheet

Canada thistle 200.150 top ten

Dalmatian Toadflax

  • Perennial
  • Yellow Flowers, similar to a Snapdragon

Link to Fact Sheet


Hoary Alyssum

  • Annual to weak Perennial
  • White Flowers with Notched Petals

Link to Fact Sheet

ha 200.165 top ten

Scotch Thistle

  • Biennial - Grows to 8 ft
  • Dark Pink to Purple Flowers with Long, Spiny Bracts at Base

Link to Fact Sheet

STtop10 200.215

Leafy Spurge

  • Perennial
  • Taproots can Extend 20 Feet Deep

Link to Fact Sheet

LS top10 200.143


  • Annual
  • Flowers are inconspicuous, greenish and lack petals

Link to Fact Sheet


Click on "Noxious Weed List" in the green bar to the left to view more weeds or refer to the "Information and Publications" section for fact sheets on the individual noxious weeds and for additional information.

Noxious Weed Control Board 
Our mission is to act as responsible stewards of the land and resources in Spokane County.

We will preserve the productivity and diversity of agricultural land and natural resources in the most cost efficient manner, from the impact of noxious weeds. We will also protect human health and environment by promoting the implementation of Integrated Pest Management control measures.
Identification and control of Class A weeds and Class B Designates weeds will be a priority and we will attempt to reduce the impact of Class B and Class C weeds to a lower level of significance. View our Noxious Weed List or our list of Weeds of Concern.

What Is a Noxious Weed?

They are non-native plants that have been introduced to Spokane County through human actions.

Due to their aggressive growth and lack of natural enemies, these species can be highly destructive, competitive, or difficult to control.

Noxious Weeds are Everyone's Problem

Noxious weeds are everyone's problem and they can not only reduce crop yields, and destroy native plant and animal habitat, they can damage recreational sites, clog waterways, lower land values, and poison humans and livestock.

The Spokane County Noxious Weed Control Board can assist you with identifying noxious weeds and give you advice on their control.