American Pondweed is a perennial plant that has both floating and a few submerged leaves in an alternate pattern. The floating leaves are elliptical to oval 4 to 7 inches long and 1 to 2 inches wide on long petioles. Submerged leaves are not abundant and are blade-like, somewhat transparent and smaller than floating leaves. American Pondweed's fruits are on spikes that often stand above the water's surface and are brownish to reddish in color, 2 to 3 inches long and 1/8 to 1/4 inches wide.
Pond Dye can be used to limit sunlight into the pond. With reduced sunlight, photosynthesis cannot occur so growth will be stunted.
There are several options to control American Pondweed.
- Use a season long herbicide such as Sonar™ A.S.. One treatment treats American Pondweed and many other common pond weeds for the season.
- Use a broad spectrum contact herbicide, such as Ultra PondWeed Defense®, will quickly kill American Pondweed. Because it does not stay in the water body, multiple treatments may be needed throughout the season.
- Use Clipper™, a fast and selective herbicide that controls tough invasive and nuisance aquatic plants.
Chemical Application Best Practices
Anytime you use chemicals treat weeds or algae, please keep in mind the following:
- Treat your pond in sections. Treat only half the pond's surface at a time, if the weather is hot, only treat 1/4-1/3 of your pond. Wait 10-14 days between treatments.
- Once the weeds have browned & died, use a weed cutter & rake to remove as much dead material as possible. This prevents an accumulation of dead plant material and muck.
- Take a proactive approach to pond management. Use PondClear™, MuckAway™ and Pond Dye to keep your pond looking great. For more information, see our article on the Airmax® Ecosystem™
Ask an Expert
If you are unable to identify your pond weed(s) using our Weed ID Guide, follow this article to email us a photo.
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