Eradicating Invasive Plants in the Central Cascades through Shared Stewardship

Release Date: Jul 3, 2019

Central Cascades — High above Swakane Canyon, Brigitte Ranne, invasive plant program manager for the Okanogan-Wenatchee National Forest is busy releasing weevils. A natural enemy of the invasive Dalmation toadflax, these little insects are just one of many tools to help get the upper on invasive plants across the Central Cascades.

“Invasive plants are a critical threat to the health of public lands and the local communities that depend on them,” said Ranne. “Our goal is to be good neighbors by maintaining healthy native plant communities and ecosystems.”

Once they become established, invasive plants often out-compete native plants- decreasing native plant diversity, degrading water quality and wildlife habitat, increasing soil erosion, and reducing forage for livestock. 

“Invasive plants don’t stop at fence lines. By sharing stewardship of this issue with state and county partners as well as local landowners, we can prevent the introduction and spread of invasives across all lands,” added Ranne.

This summer local USDA Forest Service crews will continue an integrated approach to control non-native invasive plants using herbicide application, manual methods, and biological controls such as weevils. Invasive plants to be treated include knapweed, sulfur cinquefoil, Dalmatian toadflax, Canada thistle, common tansy, St. Johnswort, scotch broom, oxeye daisy, yellow hawkweed, common hounds tongue, and common crupina. Treatment areas are signed in advance for public information and awareness including herbicide application, manual removal, and bio controls such as weevils.

2019 primary treatment areas include:

Okanogan County: Aeneas Creek and Crawfish Lake areas, Dugout Mountain, Mount Hull, and Myers Creek, Ethel Creek, Gold Creek, Marias, Nicholson Creeks and north of Mineral Hill, Big Canyon, within the area between the Chewuch and the Methow Rivers and within recently burned areas.

Chelan County: Areas in and adjacent to the 2018 Cougar Creek Fire area; Lake Chelan vicinity between Prince Creek and Moore Point, and adjacent to major forest roads and campgrounds.

Kittitas County: Table Mountain, Reecer Creek, Swauk Creek, Blue Creek, Liberty, Cougar and Lion Gulch, Teanaway, Manastash, Taneum, Upper Cle Elum Valley, Cooper River, French Cabin, Salmon la sac, Kachess, Box Canyon, Lost Lake, Cabin Creek, Stampede Pass, I-90 corridor and Gold Creek and major forest roads and campgrounds.

Yakima County: Devil’s Canyon and Little Naches drainages.

Weed treatment with weevils

Local USDA Forest Service staff release weevils to combat invasive Dalmatian toadflax in the Swakane Canyon area of the Okanogan-Wenatchee National Forest in May 2019. Credit: Dale Whaley, WSU Extension, Agronomy & Natural Resources Educator. 

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