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How to Remove Weeds From a Pond

By Charles Pearson ; Updated September 21, 2017

A pond makes a nice addition to the landscape, but many ponds are plagued with pond weeds and other unwanted vegetation. If you have fish in your pond, you may find that you have a blanket weed problem. The blanket weed thrives on the minerals that are found in fish excrement. Many ponds also have a problem with too much algae, and with weeds that grow around the perimeter of the pond. There are several ways to try to control what is growing in your pond using chemicals, aerators and other equipment.

Use pond aerators. Pond aerators can be used to add oxygen to the water, and they release carbon dioxide into the atmosphere. Once the carbon dioxide in the water gets low enough, the plants starve, and the lake weeds die. This is one of the more ecologically friendly ways to get rid of unwanted vegetation, but its usage may depend on what size your pond is and what kind of equipment you can reasonably install in it. If you have other plants that you want to live in your pond, this can also affect them.

Dye the pond water. Pond shade products can dye the water, reducing the sunlight that reaches the pond weeds. They have been shown to be safe for fish, but any plants submerged in your pond will also be affected. These are black dyes that are added to the water.

Add metallic ions like copper that have also been used to kill blanket weeds. If these are not used in the proper amounts, however, they can also kill fish and other animals, so it is important to do your research before using this kind of treatment.

Consider leaving some pond weeds. It may even be desirable to leave some weeds around your pond. Cattails and other naturally occurring vegetation can be an attractive addition around the edges of a pond. If you find the area is starting to be overrun with such plants, however, you should consider removing them.

Try using a tiller or hoe to remove weeds that you can reach. However, many of these plants have roots deep in the ground, so it may be difficult to dig them out completely.


Things You Will Need

  • Aerator
  • Dye
  • Metallic ion
  • Tiller or hoe
  • Herbicide


  • Herbicides can kill pond weeds, but they contain many harmful chemicals. They can be hazardous to fish and other animals, and many people are afraid to put too many chemicals into their pond. They can be detrimental to the environment and can deplete the oxygen in the water, leading to the death of the fish and other animals in the water. They may also have harmful effects on humans, because they can seep into the groundwater, or can be accidentally ingested by people who are swimming or boating. After a herbicide kills a plant, the plant will rot, releasing its fertilizers and consuming oxygen. This can cause odors and cause an algae problem. You may need to use an herbicide if you cannot remove them in other ways. Be sure to read about the type of chemical you use in your pond to weigh the costs and benefits, and to make sure it won't cause any unwanted, harmful effects to other plants and fish.

About the Author


Charles Pearson has written as a freelancer since 2009. He has a B.S. in literature from Purdue University Calumet and is currently working on his M.A. He has written the ebooks "Karate You Can Teach Your Kids," "Macadamia Growing Handout" and "The Raw Food Diet."