Skagit County updates noxious-weed program, reports progress on knotweed and Spartina

Skagit County on Tuesday received an annual update on the county noxious-weed program, including survey and treatment results for knotweed and Spartina, a small new garlic-mustard grant, ongoing outreach and a staffing update.

The county’s Natural Resources Division manager and the new noxious-weed coordinator told the Board of County Commissioners the program used state grant funding, seasonal crews and volunteers to run outreach, tool loans and targeted treatments last year.

The update matters because invasive plants such as knotweed and Spartina can change riverbanks and estuaries, damage native habitat and impose costs on shoreline landowners and shellfish growers. County staff said the program’s mix of monitoring, hand and chemical treatment, and grants is intended to push infestations down to small, treatable occurrences.

County staff described three grant programs and site results. On Spartina anglica, staff said the county monitors 21 sites and that seven returned negative in 2024; three sites have now met the county’s eradication threshold and are visited less frequently. ‘‘Spartina alterniflora has met complete eradication requirements in Skagit County,’’ Noxious-weed coordinator Evan Emerick said during the presentation.

On knotweed, staff presented multi-year heat maps showing heavy reductions in upper reaches of Grande (Grandy) Creek after repeated chemical and manual treatment. Emerick said crews and partners surveyed and treated river and island sites prone to seasonal flooding and that finding knotweed in Grandy Creek is now typically limited to small, scattered plants rather than dense beds.

The department also reported a new, small garlic-mustard grant of about $5,000 and a pilot removal effort on the South Skagit Highway that produced dozens of filled bags of adult plants. Staff said they plan to revisit that site earlier in the season to target rosette stages when chemical control is more effective.

Outreach and community support were a program focus. Jen Johnson, Natural Resources Division manager, told commissioners the program recorded nearly 80 direct contacts, 16 site visits and 19 outreach events in 2024 and maintains a tool-loan program that helped 11 landowners. Staff said the loan tools include uprooters, weed wrenches and injection guns and are free to borrowers.

Staff credited partners — including WSU Extension, the conservation district, Swinomish Tribal staff and state grants — for helping maintain coverage across river and estuary sites. Emerick said Spartina work required tight ‘‘track-line’’ surveys in mudflats and estuaries; he said two mapped sites alone produced roughly 225 miles of walking lines to detect plants at very low densities.

Several operational notes and next steps: the county has two vacant seats on its Noxious Weed Control Board (districts 3 and 4), the county expects seasonal hiring for three weed-aid positions and staff said their Spartina and knotweed state grants are expected to continue into the next biennium. The program also now administers four lake management districts (self‑taxing districts around Big Lake, Lake McMurray, Campbell/Superior, and Clear/Beaver) and will hold advisory committee meetings this week to plan aquatic-weed treatment for summer months.

Commissioners and staff discussed application methods and safety. Emerick described the herbicide mix used for knotweed and Spartina, application timing from early June through October with a peak in September, and required personal protective equipment tied to the product label. He said the county uses backpack and hand sprayers and adds a blue dye to solutions to mark treated plants.

A commissioner asked about balancing agricultural and aquatic work; staff said state grant funding focuses much of the work in riparian and estuary areas, while other programs — such as the county’s weed-free hay outreach — address agricultural concerns.

The program also noted two statewide noxious-weed updates: the Washington State Weed Board added round-leaf bittersweet and marsh thistle to Class A listings and Skagit County adopted those additions. Staff said neither species is known in Skagit County at present but that marsh thistle can hybridize with Canada thistle and is found closer to county borders.

Staff closed by urging residents to use the updated county web pages and EDDMapS for plant identification and to contact the noxious-weed office for site visits. Johnson and Emerick also encouraged residents to apply for board vacancies and seasonal positions.

Staff provided a contact list and said they will reapply for existing Spartina and knotweed grants this year and continue garlic-mustard surveillance and early-season treatments.

Ending: Commissioners thanked staff for the update and noted the program’s mix of field work, volunteer recruitment and grant management. The county encouraged people interested in seasonal field positions or the weed board vacancies to contact the Natural Resources Division.