Sunday Lake Invasive Plant Control

The Issue

Sunday Lake is home to an abundance of native plants. These beneficial plants are vital to keeping lakes healthy. They provide important food and habitat for aquatic life including fish, turtles, frogs waterfowl and other aquatic life. They also are important for us as they help to clean the lake by filtering pollution and prevent shoreline erosion. 

Unfortunately, Sunday Lake is also home to a few non-native invasive plants including fragrant water lily and yellow flag iris. These plants can crowd out the beneficial native plants, harm lake ecology, and interfere with swimming, fishing and boating. So while it is important to keep native plants in the lake, it can be desirable to manage invasive plants to reduce their impacts. Learn more about how the different types of aquatic plants and how to identify them. 

Invasive Lily Control Efforts at Sunday Lake

Over the years, residents have worked to control invasive fragrant waterlilies in front of their properties by hand-cutting, pulling out the roots and using an aquatic mower. However, the  infestation continued to grow covering the majority of the lake. In 2018, a group of residents formed the Sunday Lake Organization to advocate for the long-term health of the lake and the initial goal of addressing the lilies.

With funding from local residents, the group obtained a state permit and contracted with a licensed aquatic herbicide applicator to treat the invasive lilies. Treatments have occurred each summer in 2019-2021. Multiple years of treatment are needed as only a portion of the lilies can be treated each year. These treatments have been highly successful and provided relief in many areas, yet continued work is needed to address the remaining problems. 

newburstgold50_png County assistance for Sunday Lake Fragrant Water Lily Control

The Sunday Lake Organization requested assistance from Snohomish County for invasive lily control. The County was able to secure funding and offered the organization assistance for efforts in 2022 and 2023. The assistance includes paying for and managing the invasive plant treatments. 

The first step the County must take to continue the lake community's efforts is to amend its existing aquatic herbicide permit to include Sunday Lake. A public notice of the proposed permit change will be published in the Everett Herald on May 13, 2022 and May 20, 2022 

Any person desiring to present their views to the Department of Ecology regarding this application may do so in writing by June 19, 2022. Comments must be submitted to the Department of Ecology to be considered. 
Comments may be emailed to or mailed to: 

Department of Ecology, Water Quality Program

Attn: Aquatic Pesticide Permit Manager

P.O. Box 47600

Olympia, WA 98504-7600

Potential Control Actions in 2022

If the permit is approved, lake residents can expect similar control actions in 2022 as in past years when work was managed by the Sunday Lake Organization. However, the County will have the authority to treat all areas of the lake infested by fragrant waterlily. 

The first step will be to work with the Sunday Lake Community Organization to identify the treatment priorities and develop the 2022 treatment plan. Once the treatment area has been decided upon, a map will be published to the website. In addition, the County and/or contractors will conduct all permit-required notifications prior to the treatments which typically take place in later summer to early fall. The County will also use email alerts and NextDoor announcements to further notify residents. You can sign up for alerts here. 

Fragrant waterlily was introduced as an ornamental plant. It takes over shallow areas, limits habitat and boating, and causes the lake to fill in faster.

Fragrant Waterlily Patch and Flower