Lewis County Priority Weeds

Some noxious weeds are of particular concern to Lewis County Noxious Weed Control due to their limited distribution or their threat to human or animal safety. Familiarize yourself with the weeds listed below and contact our office to report a sighting, or if you could use some help in determining the best way to control these weeds on your property.

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Meadow knapweed

Meadow Knapweed – Upright stems, 20 – 40 inches tall, leaves up to 6 inches long and 1 ¼ inch wide, rose-purple flowers the size of a nickel appear in July/August. Invades moist sites including pastures, meadows, and roadsides. Found in Winlock, Vader and the Packwood area. Weed Classification: B designate

Purple loosestrife

Purple Loosestrife

Purple Loosestrife – Erect squarish stems, up to 9 feet tall, leaves 1 ½ to 4 inches long, spikes of magenta flowers 4 – 16 inches long, flowers from July to October. Invades fresh water, wetland areas. Found in wetlands and streams in the Centralia/Chehalis area as well as Stearns Creek and Mineral Lake in Lewis County. Weed Classification: B designate

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Brazilian eloda

Brazilian Elodea – Erect stems with leaves that are 1 – 3 cm long and 5 mm broad, 18 –25 mm white flowers with three petals. Grows submersed in fresh water such as ponds, lakes and quiet streams. Found in Plummer Lake and the Chehalis River in Lewis County. Weed classification: B


Eurasian milfoil

Eurasian Watermilfoil – Feathery underwater foliage, 12 or more pairs of leaflets on each leaf, leaves in whorls of 4 around the stem. Grows in still to flowing waters under many different environmental conditions. Found in Lake Scanewa, Swofford Pond, Mayfield Lake and South County Park in Lewis County. Weed classification: B Select


Tansy ragwort

Tansy Ragwort – Upright stems, 1 – 4 feet high, leaves alternate, clusters of yellow daisy like flowers, poisonous to livestock. Grows in disturbed sites, including pastures and roadsides. Primarily found in central and western Lewis County. Weed classification: B Select


Knotweed species

Invasive Knotweeds – Bamboo like stems that grow 4 – 8 feet tall, heart shaped leaves 4 – 6 inches long, white flowers appearing in August – September. Escaped ornamental invades riparian areas and roadsides. Found along many creeks and rivers in Lewis County, including the Cowlitz River, Tilton River and Chehalis River. Weed classification: B Select


Scotch broom

Scotch Broom – Shrub, 1 – 2 meters high, leaves 6 – 12 mm long, yellow flowers bloom between April and June. Grows in pastures, roadsides, riverbeds and other disturbed areas. Is present in all areas of Lewis County. Weed classification: B Select

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Butterfly bush

Butterfly Bush – Shrub, Grows up to 15 feet tall, leaves 4 – 10 inches long and 1 – 3 inches wide, 4 – 10 inch long flowers spikes usually purple in color, blooms in mid-summer. Common in landscapes, concern is escape to riparian areas and along roadways. Weed classification: B Select


Poison hemlock

Poison Hemlock – Erect Stem, 4 – 8 feet tall with mottled purple spots, finely divided leaves, lacey white flowers in late May to August, poisonous to humans. Primarily found in urban areas, alleys, vacant lots and along rail lines in Lewis County. Weed classification: B Select