Elodea canadensis is a submersed aquatic plant with elongate, often branched stems and simple linear or lanceolate leaves usually borne in whorls of 3 (at the base of a plant the leaves may be opposite on the lowest nodes). Leaves are usually 2-5 mm wide and 5-10 (13) mm long.

Plants may grow completely submersed and at some considerable depth, or in shallower water the growing tips of stems may float on the surface as in the leftmost photograph above. Flowers are unisexual and are not commonly found in our area. When they are present they are most often female. Reproduction appears to be entirely by vegetative means in our area.

Elodea canadensis is a native species, common and widespread in Wisconsin. It is similar in form to the native Elodea nuttallii and also to several alien aquatic species, including the extremely invasive species Hydrilla verticillata (first found in Wisconsin in 2007) and Egeria densa (not yet known from Wisconsin, but to be expected in the future). If you find a plant of this type regularly bearing more than 3 leaves in a whorl, it may be one of the invasive species and should be reported.