Photo: Susan Boser, Penn State University
When it comes to aquatic herbicides, there isn’t a “one size fits all” solution for aquatic plant control. Depending on the type of plant and how it is growing in the pond, there are different options for herbicides and which ones will be the most effective. For example, the product GreenClean has an active ingredient of Sodium carbonate peroxyhydrate and is most often used in granular form. It is effective on filamentous algae, but will not work to treat an emergent plant like cattail. In addition, the applicator needs to be aware if the product they choose has any water use restrictions, such as not being able to be applied to water used for irrigation or livestock water. Current populations of fish in the pond also must be considered as many copper-based herbicides like Cutrine are toxic to trout, carp and koi.
For any aquatic herbicide application in Pennsylvania, a permit is necessary and should be submitted to the PA Department of Environmental Protection (PA DEP) for review. This permit application is available on the DEP website.
If you have not recently had your pond water tested, it is a good idea to do so before applying an aquatic herbicide. Water pH and hardness can both be factors when deciding on the proper herbicide application.
More information about choosing the right herbicide for the right plant can be found in the booklet Management of Aquatic Plants.