Weed Killer for Ponds

Types

• The Virginia Cooperative Extension lists the use of chelated copper products, glyphosate, endothall, 2, 4-D, diquat and fluridone. All herbicides are sold under different trade names. Choose a herbicide after proper weed identification, as chemicals differ in effectiveness.

Function

• Products containing diquat and fluridone are most effective on submerged weeds like coontail and pondweed and also on floating weeds like duckweed. Use copper-based products to treat algae problems. Glyphosate is good on emergent weeds such as cattails and bulrushes. 2, 4-D herbicides are also effective on submerged weeds.

Herbicide to Avoid

• Endothall based herbicides are registered as aquatic herbicides by the United States Environmental Protection Agency. However the chemical is relatively toxic for fish when applied at required rates to kill weeds, as cited by the Virginia Cooperative Extension. The herbicide is not safe for ponds with fish and it is safer to use other less toxic, equally effective herbicides. Do not use endothall in livestock and irrigation water and food fish areas.