Native aquatic plants are essential to healthy lakes
Aquatic plants are a natural part of healthy lakes. They are the base of the food chain and provide key benefits to people and wildlife including:
- Better fishing – The best fishing spots are typically near plant beds for a reason - fish eat the insect larvae, snails, and other critters that living in the plants. Plant beds are also nurseries as they provide areas for fish to hide from predators.
- Beneficial habitat – Fish aren't the only critters needing aquatic plants - turtles, frogs, ducks, and songbirds, are just a few of the animals that rely on aquatic plants for food or homes.
- Erosion Control - Aquatic plants protect shorelines from waves and erosion. They also help keep sediment on the lake bottom keeping the water clearer.
- Cleaner Water – Aquatic plants can soak up pollutants from contaminated water. They also out-compete algae for limited nutrients reducing potentially harmful algae blooms.
Invasive Aquatic Plants - A Threat to Our Lakes
While native plants are important parts of lakes, you may have heard of problematic invasive plants such as Eurasian watermilfoil. These invasive plants are non natives that are overtaking local lakes and are harmful as they:
- Spread aggressively and form dense mats of vegetation
- Impede swimming, boating or other recreation
- Crowd out and replace beneficial native plants
- Harm fish and other aquatic life
Once lakes become infested with invasive plants, it is extremely costly to control them and nearly impossible to eradicate them. The best strategy is to prevent them. Since most plants are brought in by boats, you can help by making sure you Clean, drain, and dry your boat before you launch and make sure you remove all plant fragments before you leave a lake. To prevent new infestations you should also avoid planting aquatic plants in the lake or dumping aquariums in lakes and streams.
Plant Identification - Native Versus Invasive Plants
Most plants in your lake will be native species. However, many invasive plants look similar to native ones making identification difficult. To help, we have put together identification guides for the most common, local aquatic plants. We can also help with plant identification - just email a photo to [email protected] or send a sample to our office.
Aquatic Plant ControlSome landowners think they are helping the lake by removing aquatic plants in the water and along the shoreline. While intentions may be good, removing native aquatic plants is actually harmful to lake health. Native plants should be left undisturbed. However, if you are dealing with an infestation of an invasive plant species or if densely growing native plants are preventing you from swimming or using your boat, there are some control options.
Step 1: Identify your plant
Knowing the plant you are working with is essential to making a good plan. The type of plant will help you decide on the best removal strategy and will determine if there are restrictions on the amount that can be removed. You can use the online plant identification guides above or send a photo of the plant to us at [email protected].
Step 2: Read the Rules
Plant removal affects the whole lake and not just your property. Therefore, the Washington Department of Fish and Wildlife (WDFW) has established rules to try and balance the needs of homeowners and the lake health. WDFW's aquatic plant and fish booklet lays out the rules and serves as your permit for activities like hand removal and bottom barriers. There are additional herbicide restrictions (see info below). Still have questions? - we can help you find the best approach for your plant.
The amount of area you can control depends upon your type of plant as specified in WDFW's booklet.
Step 3: Decide on Area to Control Plants
- Native plants - you may only control a 10 foot corridor of native plants to provide swimming and fishing access. This means ten-feet wide section of your shoreline out into open water and NOT 10 feet along your entire shoreline.
- Noxious weeds - there is no limit to the amount for noxious weeds like fragrant water lily or yellow-flag iris. Check WDFW's booklet for restrictions on the timing of removal to avoid affecting fish spawning. If you think you have Eurasian watermilfoil, please do not try to remove as it spreads by fragments and you will likely may make the problem worse. Instead contact us for options at [email protected].
Step 4: Choose your Control Method
Hand Removal - Hand removal is the best option for removing small areas of plants - especially fragrant water lilies. People use items like weed rakes or weed “razors” to cut the plants. Once cut, remove the plants from the lake or they will decay and may cause algae blooms. There are also companies you can hire that will do hand removal of plants using SCUBA divers as necessary. Eurasian watermilfoil SHOULD NOT BE raked or pulled. Even small fragments make new plants and raking will worsen the infestation. Contact us for help with identification and control options.
Avoid raking Eurasian watermilfoil as the fragments grow new plants and make the problem worse.
Bottom Barriers - Barriers consist of burlap, landscape fabric or similar commercially available product that are placed on the lake bottom to prevent the emergence of aquatic plants. Barriers are only appropriate for small areas such as a swimming area as they smother all aquatic life. Refer to WDFW's booklet for restrictions such as the size of barriers and the amount of time they can be kept in place.
Mechanical Removal - For large-scale infestations of noxious weeds such as fragrant water lily, weed mowers or harvesters are an option. Some groups have purchased a mower for their lake and others have hired commercial operators. Mowing large areas may require permits from WDFW. Removal of plants can also be challenging on lakes that do not allow motorized watercraft.
Herbicide Treatments - There are herbicides specifically formulated for use in aquatic settings. However, ALL products that can be used in lakes are classified as "restricted use" in the State of Washington. This means they can only be applied by a licensed applicator to ensure the safety of lake users, lake residents, and aquatic life. All aquatic herbicide use also requires a permit from the Washington State Department of Ecology that will be obtained by the herbicide applicator. The permitting process ensures everyone in the area is aware of the application and has an opportunity to provide feedback. If the permit is issued, the applicator must follow certain restrictions to ensure the application is performed safely. The permit process can be expensive, so this approach is typically only used when there is a large problem and a community joins together to collectively pay for the solution.