Weeds in a stormwater retention pond can be dealt with in a variety of ways. You can remove the pondweeds by pulling them manually, treating the pond with chemicals, or by using a biological option such as introducing grass carp.

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Weed Removal in Ponds

One of the most frustrating things that a homeowner can deal with, if they live next to a stormwater retention pond, is pondweeds. There are three things that you can do to get rid of pondweeds in your pond. The first one is to manually remove them with a rake, or by hand, you can pull out the excess pondweeds. Pull them up onto the shore. They’ll dry out and become nice and light. You can then mulch mow them into your yard, and they’ll make a great compost.

The second thing that you can do is to chemically remove the weeds. Before you spray your pond with chemicals, you’ll need to first identify your weeds so that you’ll know what chemical to use. Most farm and home stores will have a section of pondweed chemicals that you can use to treat your pondweeds. Those chemicals can be applied by homeowners or your neighborhood association. But there are some chemicals that only professionals should spray. Remember to read the labels and follow directions carefully. Be smart with the way that you are spraying. Make sure that you know how much to spray, and what you’re spraying. Not every chemical is for all plants.

The third thing that you can do is a biological option. Some pondweeds can be consumed by fish, such as grass carp. Unfortunately, grass carp don’t like to eat the filamentous algae such as pond scum that floats on top of the water. But there are some other rooted plant materials that grass carp love to eat. So, if you have those in your pond, grass carp are a biological option to get rid of those pondweeds.

If you want to prevent these pondweeds from growing, there are a few things that you can do. Keep from feeding geese. Don’t let them stay at your pond all winter long. You can keep the water moving by adding an aerator or fountain. The moving water keeps the algae and some pondweeds from being able to grow and take over your pond. Also, avoid over fertilizing. Too much fertilizer on a lawn or extra fertilizer outside your lawn can wash into your pond, which causes your pondweeds to grow instead of your grass.

This feature story prepared with Tonya Bronleewe, Kansas State University Research and Extension Agriculture and Natural Resources Agent, Sedgwick County. For more information, visit your local county extension office or visit our website at KansasGreenYards.org.

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