Frequently Asked Questions

Noxious weeds are non-native plants that have been introduced accidentally or as ornamental in peoples’ gardens. Some are poisonous to humans and livestock and most grow rapidly and are extremely difficult to control. They can reduce crop yields, displace desirable plant species, destroy beneficial native habitat, damage recreational opportunities, clog waterways and diminish land values.

The State Noxious Weed Board, a group of citizen volunteers representing all parts of the state, annually adopts and publishes a list of weeds to be controlled or eradicated based on public comment and input from county weed boards.

You may call the Douglas County Extension office at 509-745-8531 to help you identify the weeds and offer control recommendations.

You may call the Douglas County Extension office at 509-745-8531 and discuss the issue with them.

Douglas County Transportation and Land Services is responsible for controlling weeds that grow along the County’s road right-of-ways. Contact Douglas County Transportation and Land Services at 509-884-7173 for questions or concerns regarding weeds on the right-of-ways or on County owned property.

It will depend on what noxious weeds you have, their stage of growth and other site-specific variables. Please contact Washington State University (WSU) Extension for more information on herbicides. Remember to always follow the label directions when applying herbicides.

Because just like a leaky roof or poor foundation, noxious weeds are a detriment to the value of the property and will take time and money to get under control.

Contact the local Washington Department of Agriculture or Washington State University (WSU) Douglas County Extension.

Generally you will find that this form of control will not work all summer because the plants will start to bloom lower than your mower blade. Mowing is one important method in stopping seed production, but should be used along with other control measures to stop the spread of noxious weeds. 

For example, mowing is not entirely effective on Spotted knapweed or Leafy spurge, but a diligent 3 year mowing program on Canada thistle may achieve around 90% control if mowed at the early bud stage of growth (several times during the growing season) followed by a fall application of herbicides. This will increase the control efforts and help to cause the thistle to collapse.

This is an open invitation for noxious weeds to come into an area. If land is not managed correctly, then the most aggressive, non-native plants that are established nearby may take over an area, choking out native grasses and forbs. The knapweed infestation in Montana is contributing to the death of over 200 elk per year and several cattle ranches have been abandoned due to the overwhelming invasion of Leafy spurge and knapweed.

It is important to keep in mind that biological control is a slow process and will not eradicate noxious weeds. However, they do have their place in an integrated pest management plan. When used in conjunction with mechanical, cultural and/or chemical control methods, bio control can improve the overall efforts.

Most herbicides are considered low or moderately toxic. All chemicals have a half-life in the environment. Half-life is defined as the amount of time it takes the biodegrade one half of the original amount. herbicides are broken down by sunlight and microbial activity in the soil.