Noxious Weed Board

The Lewis County Noxious Weed Control Board will hold its regular quarterly meeting on August 5th, 2026, at 10 AM in the Community Development Hearing Room at 125 NW Chehalis Ave., Chehalis, WA 98532. The agenda for this meeting is available here.

As summer comes to an end and the days get shorter, it’s easy to put weed control on the back burner. But fall is actually one of the best times to take a walk around your property and tackle some of our most troublesome invasive weeds.

Many perennial weeds are preparing for winter, and their energy is moving from the leaves down into their roots. That makes this a particularly good time to treat plants and reduce the chances they will return next year.

Tansy Ragwort

Tansy ragwort is one of the weeds we see frequently in pastures, roadsides, and other open areas. Its bright yellow flowers may look harmless, but tansy is toxic to livestock and can produce thousands of seeds.

If you find tansy on your property, don’t let it go to seed. Pulling or digging individual plants can be effective for small infestations. Larger infestations may benefit from a properly timed herbicide application, particularly when plants are actively growing in the fall.

Himalayan Blackberry

Himalayan blackberry is another familiar—and frustrating—sight. Cutting it down may make an area look better for a while, but blackberry has a persistent root and crown system that allows it to quickly grow back.

Fall can be a good time to treat blackberry because the plant is preparing for winter and moving resources into its roots. Herbicide applications to actively growing foliage can be an important part of controlling established blackberry, especially when combined with cutting, digging, or other appropriate methods.

Knotweed

Knotweed, including Himalayan knotweed, can be particularly challenging to control. Its extensive underground rhizomes allow it to survive and spread, and even small pieces of plant material can potentially start new infestations.

Fall is an important treatment window for knotweed. As the plant begins moving energy into its underground rhizomes, properly timed herbicide applications can help target the plant below ground. Knotweed often requires several years of treatment and monitoring, so early detection and persistence are key.

🌿Take a Walk This Fall

You don't have to be a weed expert to get started. Take a walk around your property this fall and look for tansy ragwort, blackberry, knotweed, and other invasive plants. Pay particular attention to fence lines, roadsides, pastures, stream corridors, and areas where the ground has been disturbed.

The sooner you find an invasive weed, the easier it is to control.

If you have an infestation you aren't sure how to handle, contact our office for information about identification and management options. A little time spent this fall can save a lot of time—and a lot of weeds—next year.

And remember: when using herbicides, always read and follow the label. Choose a product appropriate for the target weed and location, and take care to protect people, pets, livestock, pollinators, water, and other sensitive areas.

This fall, take a walk, spot those weeds, and make a plan. Your future self—and your property—will thank you!