Canada Waterweed

[ Elodea canadensis ]

Canada Waterweed (Elodea canadensis) is common in the Northern and North Central states south to Kentucky and Virginia. Sometimes referred to as American elodea, common elodea and waterweed. Elodea can grow into dense populations that reach to or near the surface easily prohibiting recreational water use.

Note: See also Hydrilla an exotic submerged plant found in the Southern states that looks similar.

Canada Waterweed > Averages three leafs per whorl with smooth leaf edges.

Hydrilla > Averages three to five leafs per whorl with rough toothed leaf edges.

Canada Waterweed
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Canada waterweed lives entirely underwater with the exception of small white flowers which bloom at the surface and are attached to the plant by delicate stalks. It produces winter buds from the stem tips which overwinter on the lake bottom. It also often overwinters as an evergreen plant in mild climates. In the fall leafy stalks will detach from the parent plant, float away, root, and start new plants. This is Canada waterweed's most important method of spreading, with seed production playing a relatively minor role. It will grow in a wide range of conditions, from very shallow to deep water, and in many sediment types. It is found throughout temperate North America.

Q. What are the best control options?

Herbicide Application:
Hydrothol 191 Granular is a favorite, it is easy to apply and very broad spectrum. An alternative is Reward liquid herbicide equally effective and broad spectrum. Most people prefer the granular Hydrothol because of its easy to apply granular formulation.

Elodea plant fragments can develop into new plants. If you are going to physically cut or rake this plant for control we suggest limiting the control size.

Q. When is the best time to treat?

Once water temperatures are around sixty degrees or warmer however this plant responds equally well to herbicide treatment when mature.

Q. How do I actually apply the product(s)?

The Hydrothol 191 granules can be spread by a small Hand held spreader or can be tossed by a hand scoop. The Reward should be applied by a hand held or Solo backpack sprayer.

Q. How often do I need to treat Elodea?

One treatment per season is usually enough.

Q. How long before I see results?

Generally within two weeks things will be cleared up. Maybe even sooner with Elodea.