Algae & Water Weed Guide

This Water Weed Guide is designed to help pond owners identify and manage aquatic weeds and algae in their lakes and ponds. Management of most aquatic plant species depends on properly identifying the desirable or nuisance plant. Our aquatic weed control product recommendations are based on over thirty years of field experience with the do-it-yourselfer in mind. These are general recommendations that typically work when used according to the product label. Our biologists may choose to use other products and solutions when on site as the water chemistry of each pond is unique. We also carry products to rid your property of nuisance geese.

The following pages picture common aquatic weeds throughout the country. Place your weed in a clear glass jar with water and compare it to the pictures. Pay careful attention to the leaves. Keep in mind prior to implementing any control method that plants are a necessary and beneficial component of healthy pond ecosystems. Nevertheless, plants can cause problems and control measures to eliminate or reduce overabundance are available.

To get started, click on the group of aquatic weeds to which you feel your problem weed belongs and work through the examples until you find it. Refer to the aquatic weed zone map if unsure which group of aquatic weeds your issue belongs to.

Aquatic Weed Groups

Problem Algae
Submerged Weeds
Floating Weeds
Emergent & Terrestrial
Algae on Paddle EWM
Watermeal White Water Lily

Phragmities Aust.

Aquatic Weed Zone Map

Pond Zones


Image Source: SePro

In Wisconsin and other states, chemical use permits are required for all herbicide/algaecide applications or you must have in place a current Type I or Type II fish farm license. Check with your local and/or state regulatory group for specific requirements. In order to apply chemicals in liquid form within Wisconsin, the applicator must be licensed with the State. Wisconsin pond owners - contact the Department of Agriculture at 608-224-4887 for a fish farm license.