WDFW to treat Mattoon Lake near Ellensburg for noxious weeds week of July 20


David Heimer, 253-732-3869
Rachel Blomker, 360-701-3101

ELLENSBURG – The Washington Department of Fish and Wildlife (WDFW) will use herbicide treatments to control noxious weeds at Mattoon Lake in Kittitas County the week of July 20.

Treatment work will not impact fishing or other recreation at the lake per the herbicide labels and the Washington Department of Ecology permit requirements. Signs will be posted at the lake advising visitors of the treatment work.

The western end of Mattoon Lake will be treated with the herbicide ProcellaCOR to control Eurasian and hybrid watermilfoils. WDFW will also treat the lake shoreline with the herbicide imazapyr to control yellow flag iris, an emergent plant that impedes casting access for anglers.

“Yellow flag iris and Eurasian water milfoil are invasive, non-native plants that choke out native habitat for fish and wildlife if allowed to spread,” said David Heimer, noxious weed coordinator for WDFW. “We will use a new herbicide this year that has a high affinity for milfoil and degrades rapidly, so we’re hoping for excellent results.”

The weed control work is made possible by a Washington Department of Ecology grant and input from the Kittitas Noxious Weed Control Board and local anglers.

The Washington Department of Fish and Wildlife is the state agency tasked with preserving, protecting, and perpetuating fish, wildlife, and ecosystems, while providing sustainable fishing, hunting, and other recreation opportunities. 

Individuals who need to receive this information in an alternative format, language, or who need reasonable accommodations to participate in WDFW-sponsored public meetings or other activities may contact the Title VI/ADA Compliance Coordinator by phone at 360-902-2349, TTY (711), or email (Title6@dfw.wa.gov). For more information, see https://wdfw.wa.gov/accessibility/requests-accommodation.