1. Himalayan Knotweed

    Persicaria wallichii Himalayan Knotweed - A clumping perennial with hollow stems and creeping rhizomes. It grows about 6 feet in height.Leaves: Leaf shape is elongated compared to other knotweeds and are around 5-12 inches in length. They are leathery and alternate along the stem.Flowers: Flowers bloom from July-October. Whiteish pink flowers that are fragrant grow at the tips of branches.Habitat: Grows in disturbed, moist sites like roadsides, riparian, and wetland areas.Weed Classification: B DesignateWhy is it a Noxious Weed?This plant vigorously grows into dense stands that overtake native vegetation and alter ecosystems. It can survive severe floods and spread plant …


    Weed Control - Oct. 5, 2022, 4:16 p.m.

  2. Curlyleaf Pondweed

    Potamogeton crispus Curlyleaf pondweed - The entire plant stays underwater, except for the flower stalk, and usually only grows in the spring before dying off in the late summer.Leaves: Leaves are alternate along the stem, submerged, and oblong in shape. They are also stiff with distinctly wavy edges and fine teeth.Flowers: Flowers bloom from June-August. Flowers are very small and have 4 petal-like lobes.Habitat: Grows in shallow or deep water that can either be still or flowing and tolerates disturbances.Weed Classification: C SelectWhy is it a Noxious Weed?This plant can form dense colonies on the surface that interfere with aquatic …


    Weed Control - Oct. 5, 2022, 4:38 p.m.

  3. Get Outside and Get Garden Wise!

    Mother Nature has decided to bestow upon us some glorious sunshine, and if you ask us, timing couldn’t be better because April just happens to be National Garden Month! Now is the time to get out, get dirty, and get garden wise!Escaping the home garden or landscape setting is one of the primary pathways that “ornamental plants” become “invasive plants” in Washington State. Once established, these “ornamentals” can outcompete native vegetation and, ultimately, change the entire ecosystem from the ground up. Once a habitat lacks native vegetation, there is no longer a food source for native insects, without an insect …


    Weed Control - April 9, 2020, 9:14 a.m.

  4. Scotch Broom

    Cytisus scoparius Scotch Broom - Everyone's favorite noxious weed! A woody perennial shrub that has many branches. Plants can range from 3-10 feet tall.Leaves: Scotch Broom has few leaves. The upper leaves are simple with the lower leaves being 3 parted. Leaves are pointed at each end and can fall early in the year, leaving bare, green stems.Flowers: Flowers bloom from March through June. Typical pea family flowers in shape. Bright yellow in color with 5 petals.Habitat: Typically, can be found along roadsides, in pastures, grasslands, and open areas with recent soil disturbance.Weed Classification: B SelectWhy is it a Noxious …


    Weed Control - Sept. 29, 2022, 9:48 a.m.

  5. Class Bs of Concern

    The Class Bs featured here are either already found in Lewis County or have been confirmed in neighboring counties and are likely to be introduced. Weeds are often spread unintentionally through the movement of materials, such as hay, dirt, gravel, and woodchips. They are also brought in by pets, animals, floods, ATVs and other vehicles, and watercraft. Finally, many are brought in intentionally as ornamentals by those who are unfamiliar with the noxiousness of that particular species. It is very important to recognize noxious weeds so that you can have a better understanding of your risk of transporting seeds or …


    Weed Control - March 5, 2015, 1:44 p.m.

  6. Controlling Noxious Weeds

    Identification and control of some common Lewis County Noxious Weed Species


    Weed Control - March 31, 2023, 12:15 p.m.

  7. Brazilian Elodea

    Egeria densa Brazilian Elodea - Also known as Brazilian Waterweed, its a fully submerged ornamental that is used primarily in fish aquariums.Leaves: Lower leaves grow in a whorled formation and typically consist of 4 leaves per whorl. Upper portions of stem often appear more dense than the base. Color can vary from bright to dark green depending on light availability, time of year and growing conditions.Flowers: Small white flowers with 3 petals and yellow center, on thread-like stems will often breech the water's surface when in bloom. Blooms in summer.Habitat: Can infest the beds of freshwater lakes or rivers or …


    Weed Control - Sept. 26, 2022, 11:01 a.m.

  8. Yellow Archangel

    Lamiastrum galeobdolon Yellow Archangel - Evergreen to semi evergreen plant that grows very quickly. It is mostly a trailing perennial, though it can grow upright if climbing other plants.Leaves: Opposite and oval shaped. Toothed and hairy typically with silver-gray markings.Flowers: Flowers bloom from April through June. Flowers are small, yellow, and two lipped. The upper lip is hooded, and the lower lip has orange/brown markings. Flowers grow in whorls.Habitat: Yellow Archangel can grow in shade or sunlight. Can sometimes escape people's landscaping into nearby forests, greenbelts, and riparian habitats.Weed Classification: B SelectWhy is it a Noxious Weed?Escapes easily from gardens …


    Weed Control - Sept. 29, 2022, 9:49 a.m.

  9. False Brome

    Brachypodium sylvaticum False Brome - A perennial, loosely tufted grass with upright stems.Leaves: Leaf sheathes have spreading hairs (can be hairless). Leaf blades are flat and arched up to 14 inches long. Leave blades are covered with long soft hairs.Flowers: Flowers bloom from April-June. Flowers are grouped in upright to nodding spikes. Flowers vary in hairiness and typically don't have stalks connecting them to main stem.Habitat: Grows in a variety of habitats including: forests, forest edges, woodlands, riparian areas, prairies, and roadsides.Weed Classification: AWhy is it a Noxious Weed?It spreads very fast and outcompetes native flora. Can form dense monocultures …


    Weed Control - Sept. 29, 2022, 10:46 a.m.

  10. Poison hemlock, poisonous to animals and man

    Be alert this spring for Poison hemlock (Conium maculatum), a noxious weed poisonous to sheep, cattle, swine, horses and man.  Animals can become poisoned by eating a small amount of the plant. Poison hemlock is common to Lewis County but not a wide spread noxious weed. Often it is associated with old farmsteads and disturbed vacant lots in urban area. The plant can reach a height of three to six feet tall and has light green foliage at flowering. Hemlock flowers in late May and June. Later the plant will die back with stalks that are straw colored and the …


    Weed Control - April 14, 2015, 8:38 a.m.