Weeds and ponds are a bad combination. They are not visually appealing, they make it difficult to fish and a quick dip in the pond will be more of a challenge.
Pond owners can follow a general rule to try and eliminate this occurrence from their fishing experience: if your pond was weedy last year, then chances are you’ll have a similar problem this year. Herbicides are a tool that can be used to help manage these weeds.
However, while they are a quick means of knocking back pond weeds, Marley Beem, Oklahoma Cooperative Extension Service aquaculture specialist with Oklahoma State University’s Division of Agricultural Sciences and Natural Resources, warns that care should be taken in the use and selection of herbicides.
“Using improper herbicides puts you and the environment at risk. We all like a bargain, but should not consider using herbicides that are not specifically labeled for ponds and other aquatic sites,” Beem said. “Only herbicides labeled for aquatic use have been tested for the safety of the environment, fish and the people who eat those fish.”
Even with proper aquatic herbicides, Beem said there are some sites in which herbicides should never be used. These include ponds that are excavated below the water table and fill from the bottom up; ponds in places like the bottom of gravel quarries or sandy river bottoms as groundwater may flow into someone’s water well; and ponds that can overflow into public waters.
“Occasionally plant management is needed in creeks or flowing water situations. In this case, contact state agencies, such as the Oklahoma Department of Wildlife Conservation before any application is made,” Beem suggested. “When what you do on your property may affect others, be very cautious and proceed only with expert advice and approval.”
County Extension agriculture educators will be able to help pond owners in developing a pond weed management plan. It is essential that you correctly identify the plant, understand how to calibrate your application method and be aware of the needed withdrawal time to protect livestock, swimmers and other pond users.
“Another hazard in treating pond weeds is killing too many at one time and causing so much plant decay that all dissolved oxygen is used and your fish die,” Beem said. “Take care in their selection and use so that your enjoyment of the pond is not overwhelmed by problems resulting from anherbicide application gone wrong.”