Eastern Washington Noxious Weeds Information and Resources

Eastern Washington is home to a variety of noxious weeds that can harm the environment, wildlife, and the economy.

The Scotch broom is one of the most widespread noxious weeds in Eastern Washington, covering over 1 million acres. It's estimated that it costs the state over $50 million annually to control.

The Washington State Noxious Weed Control Board identifies the Scotch broom as a Category 1 noxious weed, meaning it's a high priority for control and eradication.

The Russian knapweed is another noxious weed that's found in Eastern Washington, and it's known to outcompete native vegetation for water and nutrients.

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Manual methods for removing noxious weeds like Japanese Knotweed include cutting, mowing, pulling, digging, or covering.

Cut stems close to the ground every two weeks throughout the growing season to prevent new shoots from growing.

Digging is most effective in loose soil, where you can easily dig up surface roots.

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Check frequently for new shoots and dig them up as soon as you notice them to prevent regrowth.

Covering the area with black plastic or other impermeable material can also be an effective method, but it's a long-term process that may take several years to eradicate the weed.

Rototilling is not recommended, as it can make hundreds of new plants grow from the tiniest root fragment.

For more information on controlling noxious weeds, check out the King County Noxious Weed Control Program's resources on invasive knotweeds and knotweed biology and control.

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In Washington State, noxious weeds are classified into three categories: Class A, Class B, and Class C. Class A weeds are non-native species whose distribution is still limited, and it's required by law to remove them.

The Washington State Noxious Weed Control Board is responsible for classifying these weeds. They also maintain a list of Class A, Class B, and Class C weeds.

You can find the Washington State Noxious Weed List on the US Department of Agriculture's website. This list is a great resource for checking whether a plant is considered a noxious weed.

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Diffuse Knapweed is a biennial thistle that can mature and flower at a wide variety of heights - anywhere from a few inches to a few feet tall.

It's a type of plant that can grow quite tall, so be sure to keep an eye out for it.

Diffuse knapweed is known for its ability to thrive in a variety of environments, making it a bit of a challenge to control.

The scientific name for diffuse knapweed is Centaurea diffusa.

Russian thistle is a sneaky plant that's often overlooked when it's young and slender, but becomes a large, spiny, brown tumbleweed as it matures.

The Washington State Noxious Weed Control Board maintains lists of foreign plants that must be removed or controlled, and it's the property owner's responsibility to take action.

English ivy, knotweeds, Scot's broom, and tansy ragwort are just a few of the extensive problems west of the Cascades, while knapweeds, leafy spurge, and thistles degrade eastern portions of the state.

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Loosestrife, milfoil, and parrotfeather clog waterways, and Spartina and reed canary grass alter shoreline ecosystems.

The Washington State Noxious Weed Control Board classifies non-native, harmful plants into three categories: Class A noxious weeds, Class B noxious weeds, and Class C noxious weeds.

Class A noxious weeds are non-native species whose distribution in Washington State is still limited, and it's required by law to remove them.

Class B noxious weeds are non-native species whose distribution is limited to portions of Washington State, and it's essential to control them to prevent further spread.

Class C noxious weeds are widespread in Washington or are of special interest to the agricultural industry, and while they may not be as pressing, they still require attention to prevent harm.

The Washington State Noxious Weed Control Board classifies non-native, harmful plants into three categories: Class A, Class B, and Class C. Class A noxious weeds are non-native species whose distribution in Washington State is still limited, and it is required by law to remove them.

The Board has a list of noxious weeds that are broken down into these categories. You can check the Washington State Noxious Weed List from the US Department of Agriculture for the most up-to-date information.

In Washington State, non-native species whose distribution is limited to portions of the state are classified as Class B noxious weeds. These plants are considered a threat to the environment and can outcompete native plants for resources.

The Washington Department of Ecology also has a list of aquatic plants that are considered invasive. You can check their website for more information.

The National Invasive Species Lists are also a valuable resource for checking whether a plant is invasive or a noxious weed. These lists can help you identify plants that are not yet officially listed as invasive in your area, but may still be a threat.

Some examples of invasive plants in Washington State include English ivy, knotweeds, Scot's broom, and tansy ragwort. These plants can be found in many areas of the state and can be difficult to control.

It's essential to be aware of the invasive plants in your area and take steps to prevent their spread. You can start by checking the resources listed above and learning more about the plants that are invasive in your region.

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In Washington State, the Washington State Noxious Weed Control Board classifies non-native, harmful plants into three categories: Class A, Class B, and Class C noxious weeds.

The board requires property owners to control listed noxious weeds on their land, which means homeowners and private or public entities must take action.

English ivy, knotweeds, Scot’s broom, and tansy ragwort are extensive problems west of the Cascades.

Knapweeds, leafy spurge, thistles, and many others degrade eastern portions of the state.

Loosestrife, milfoil, and parrotfeather clog waterways.

Spartina and reed canary grass alter shoreline ecosystems.

Tree-of-Heaven, also known as Ailanthus altissima, is an aggressive invasive plant that sprouts up through landscape plants and lawns, and right up against concrete foundations.

It spreads by seed, which can be dispersed by birds but especially by wind, and by root sprouts.

If you suspect you have Tree-of-Heaven in your neighborhood, you can check the Invasive Plants Atlas of the United States for clear images and information.

The Washington State Noxious Weed Control Board is considering a nomination to designate it as a Class B noxious weed for the 2012 state weed list.

You can encourage your neighbors to eradicate it when possible, and get every last bit of root to prevent regrowth.