One of the quickest ways to reduce the enjoyment level of your pond is to let it get covered in vegetation. Unfortunately, our weed pressures are such that this is often the case.

Control programs have to start with a proper identification of the problem species. KSU’s Aquatic Plants and Their Control (link below) is a great resource. If you want color pictures, check out the aquatic weed management website at Texas A&M at: http://aquaplant.tamu.edu/ .

Once species are identified, it’s time to think about control. Your options are varied.

Preventative measures focus on the physical features of the pond. Clear, shallow water bodies that are high in nutrients often see prolific plant growth. If possible during new construction, make sure excavation encourages adequate depth. Older ponds can be cleaned to increase depth as well. Implement filter strips or other management practices upstream of the pond to reduce sediment loads that can increase nutrient density.

Mechanical control efforts can be effective, but typically require lots of labor. Start by pulling or raking out marginal plants or removing submersed plants by pulling a cable or chain through them. V-shaped weed cutters can be thrown out into the water and pulled back, cutting the weeds off so they can be raked to shore. Even shading with a fine mesh, dark plastic screen is an option. Mechanical control is typically short lived and most effective in smaller bodies of water. It is best used in conjunction with biological and chemical control methods.

Numerous herbicides are available for chemical control. Species identification is one of the most important facets of chemical control, as is proper application according to product labels. Most labeled products are very safe for fishing, swimming, etc… after application, so long as label guidelines are followed. If a large portion of the pond is covered in vegetation, avoid treating the entire area at one time. Decomposing vegetation uses up oxygen. This oxygen is taken from the water, meaning less is available for aquatic life living in the pond, potentially causing fish kills. Products may be expensive and are not typically as readily available as many of our common herbicides. Be sure to read and understand product labels before purchasing.

Biological control typically consists of grass carp since they will feed on many species of floating and submerged plants. They won’t necessarily control an established infestation of weeds, but can keep them eaten off if allowed to stay ahead of them. As many as 20 fish per acre may be required, but they can be a nice addition to your pond at an inexpensive price. They will readily leave the pond during heavy water flow so be prepared to restock as necessary.

Aquatic weed control methods are as varied as the vegetation present in our ponds. If you have questions about them, don’t hesitate to contact us. The K-State Research & Extension publication Aquatic Weeds and Their Control is a great resource as well. It is available via your District Office or online at: http://www.bookstore.ksre.ksu.edu/pubs/c667.pdf .