Invasive Aquatic Plants & Treatment



What is it: 


Milfoil is an aggressive noxious aquatic plant invader in Washington state.  Within a few years of introduction, it forms dense mats that shade and crowd out other aquatic native plants, can alter aquatic ecosystems, degrades water quality, inhibits water flow, impacts recreational activities, and reduces habitat quality for fish, waterfowl, and other wildlife.  The dense growth also can be a hazard to swimmers and a nuisance to boaters.  


Curly-Leaf Pondweed


What is it:


Curly-leaf pondweed is a Eurasian native, which is now found nearly worldwide. It can become invasive, forming dense surface mats that choke out native plants and affect recreational uses. Since it starts growing earlier in the spring than most native pondweeds, it can often outcompete other plants. Curly-leaf pondweed reproduces by seed, rhizome, plant fragments and turions (hardened stem tips that drop to the sediment), all of which can be dispersed by water, boating equipment, or clinging to animals. It grows in still or slow-flowing, shallow to deep, freshwater. Curly-leaf pondweed is tolerant of disturbance, low light, and slightly brackish water. It grows best in cool water, going dormant as the water warms. In Washington State, curly-leaf pondweed is a C-class noxious weed. It has been found in many sites scattered around the state.



Lake Management District (LMD):


The Lake Management District was established to help with the control of milfoil and other potential aquatic and/or riparian noxious weeds.  The citizens steering committee provides advice and makes recommendations to the county as to the management and administration of the lake management district and the control of the Eurasian Milfoil, Curly-Leaf Pondweed, and other potential aquatic and/or riparian noxious weeds.


Herbicide Control:


The use of pesticides in water is regulated in Washington State. All applicators must have an aquatic endorsement on their pesticide applicators license, which is issued by the Washington Department of Agriculture. In addition, coverage under a permit issued by the Department of Ecology is required.


Loon Lake will be treated with Galleon, Aquathol K, and Aquathol Super K Aquatic Herbicide on or about June 27th-July 8th, 2022, and another one or two rounds of ProcellaCOR Aquatic Herbicide treatments will occur July 11th-August 19, 2022, weather permitting.  Up to three applications are planned. 


The applicator (AquaTechnex) will post signs in the treated and potentially affected areas no more than 48 hours prior to treatment.  The signs will describe any water use restrictions or advisories. 


Please refer to for the most up-to-date treatment information.  Treatments will not take place on weekends or holidays. 


We appreciate your cooperation while the application is taking place.  













*********************************** Meeting Notice




Your Lake Needs YOU!

Consider becoming a Member of the LLPOA!


Regular Monthly Meeting 

September 15, 2022

6:30 pm


Historical Old Schoolhouse 

4000 Colville Rd,

Loon Lake, Wa


 LLPOA Meetings are the second Thursday  of each month March-Oct


Email us at:


Loon Lake

Property Owners Association

PO Box 165

Loon Lake, WA 99148


Annual dues

only $50 per family


Meeting Notice:


Lake Management District Advisory Committee


September 12, 2022

6:30 p.m.


Historical Old Schoolhouse

4000 Colville Rd, Loon Lake


LMD Meetings are held the second Monday of each month

March - Oct


For information on how Milfoil and/or Invasive Aquatic Plants impact the lake and what's being done to mitigate it, the public is encouraged to attend these informative meetings.



Upcoming Events:


Dock Demo 

Canceled Until Further Notice



Please check the calendar for additional upcoming events and  activities 



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