Aquatic Plant Management - Mechanical Cutting

Description of Method

Mechanical weed cutters cut aquatic plants several feet below the water's surface. Unlike harvesting, cut plants are not collected while the machinery operates. There are two types of underwater weed cutters commercially available, including:

Cutting is generally performed during the summer when plants are near the surface.

Jenson Lake Mower mounted on bow of boat

Portable Boat-mounted Cutters

An electric boat-mounted underwater cutter cuts a four-foot wide swath up to seven feet below the water's surface. It is effective in removing submerged (e.g. hydrilla), floating (e.g water lilies) or emerged (e.g. cattails) plants. It has been reported that it takes about three hours to clear one acre of plants using this device. The Jenson Lake Mower™ pictured right, starts at about $3,000 and cuts about seven hours on a fully charged 12 V deep-cycle marine battery. The accompanying five-foot wide boat-mounted Jenson Rake™ can remove cuttings, or floating plants (e.g. salvinia and hyacinth). By making a clean cut and removing the cuttings, propagation from fragments is minimized. Portable underwater cutting units can be installed on pontoons, paddle boats, or 14-foot or longer utility boats.

Specialized Underwater Cutters

Specialized underwater weed cutters can cut weeds in water as shallow as ten inches and as deep as five feet. The main sickle will cut a swath ten feet wide. It has been reported that specialized cutters can cut about 12 acres per day.

boat with 10 foot aquatic weed sickle attached to bow


Cutting generates floating plants and fragments. It is important to remove all plants and fragments from the water to prevent them from re-rooting or drifting onshore. Cleanup can be accomplished using a weed rake. However, specially designed nets should be used when using boat-mounted and larger underwater cutters. The time needed for cleanup depends on the density and types of plants and the amount of acreage cut.




Mechanical cutting in Washington requires hydraulic approval, obtained from the Department of Fish and Wildlife. For projects costing over $2,500, check with your city or county to see if a shoreline permit is required.


Portable boat-mounted cutting units cost from $400 to $3,000. Specialized underwater cutters cost about $11,000.


The following list of vendors is provided for your information. It is not our intention to endorse or promote specific vendors or products and this list may not be comprehensive. Vendors who wish to be added to this list should contact us.

Please contact the companies directly if you would like more information about their products.

Jenson Lake Mower™
Jenson Technologies Development Corporation
412 Summer Mountain Drive San Marcos, Texas 78666
Toll Free: (888) 298-5253
Tel. 512-393-5073
Fax 512-393-5074
Hockney Underwater Weed Cutters
Hockney Co, 913 Cogswell Drive
Silver Lake, WI 53170
(414) 889-4581

Aquarius Systems
Makers of aquatic weed harvesters and cutters
200 North Harrison Street
North Prairie, WI 53153
(262) 392-2162

Aquatic Vegetation Groomer
Contact Lake Weeders Digest at:

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