In small quantities, pond weeds can give your garden pond a natural look and feel. However, when the growth gets out of control, pond weeds can become a nuisance you need to manage. As the temperatures rise in summer, you tend to spend more time outdoors and enjoy your garden. 

While a clean and pretty pond can be a source of freshness and peace in a garden, overgrown weeds can turn an idyllic water body into a smelly and stressful garden feature. As a pond owner, you want to maintain the appearance and charm of your water feature without any of the disadvantages of pond weeds. 

The key to pond weed control is to identify which aquatic vegetation is the source of your problem. This will help define the best solution to clear your pond and protect it in the long term. Here are our best pond weed control tips to get rid of unwanted weeds without damaging your pond. 


What types of aquatic weeds grow in your pond?

Aquatic weeds tend to become a problem during the warmer months of the year when the pond water temperature rises above 43F°. The higher the temperature gets, the more pond weeds will grow and fill the pond. Depending on the purposes of your pond, you may have different needs for pond weed control. A pond that also serves as a refreshing pool, for instance, will require almost complete weed eradication. If your pond acts as a wildlife ecosystem, on the other hand, you don’t want to eliminate all the weeds. Indeed, pond creatures may use the weeds for cover and protection. 


You will find three main types of pond weeds: 

  • Submerged plants or oxygenators
  • Emergent or marginal weeds
  • Floating plants


Submerged weeds are generally good for the pond as they provide cover for aquatic creatures. They grow underwater and have flowering shoots that reach above the surface. These weeds are oxygenators. Some species, however, can be troublesome as they can take over the pond surface and deprive the pond of more desirable aquatic plants. 

Emergent weeds grow in shallow water. They can be highly invasive and cut off the oxygen supply to other plants. 

Floating plants can cover the entire surface of the water, depriving creatures and other plants of direct sunlight. They can also make the water appear brown or green, which can be dangerous for young children or animals as they can fall into the pond. 

Most weeds can be managed through regular maintenance and dedicated control. 


What are the pond weeds to control in priority?

The most frequent nuisance for pond owners are four specific types of pond weeds: 

  • Muskgrass or Chara
  • Cattails
  • Sludge bottom or rocky bottom weeds
  • Duckweeds


Muskgrass is a floating plant that is highly common in ponds of all sizes. Most pond owners are familiar with its dark green branches and crunchy texture. Muskgrass is also called skunkweed, which is a clue to its worse feature: Its foul odor. Don’t confuse it with submerged flowering plants. Muskgrass has no flowers. 

Cattails are emergent weeds that shoot a brown sausage-like stem out of the water. They are typically found in boggy areas. While they are often perceived as an attractive feature, cattails can reach up to 10 feet in height. As a result, they can drive away birds and wildlife that can access the water anymore. 

Pond sludge or rocky bottom weeds consist of decaying algae and waste. They are the leftovers from dirt and aquatic weeds. As a result, the buildup can affect the quality of the water and deprive more desirable plants and aquatic creatures of oxygen. 

Duckweeds are floating weeds, which can cover the whole surface of the pond. Also called water lenses, duckweeds can deprive aquatic plants and fish of oxygen. Another floating species that can put your pond at risk is blanket weed, aka a blanket of weed. 


You will find all the necessary pond weed control treatments for large ponds on our website. But here’s a brief overview of how to use them to tackle your pond issues. 


Treating floating algae

Muskgrass and duckweed can both be removed manually. However, we appreciate it would be a lot of work! We recommend instead using a product that can be directly applied to troublesome floating algae, such as the AirMax Pond Logic Algae Defense. The Algae Defense product is safe to use in freshwater, fish ponds, and even reservoir water because it doesn’t affect the safety of the water. As such, your pond remains safe to use for recreational activities and keeping wildlife creatures. 


Removing cattails

Cattails can be removed in a variety of ways. You can choose to deploy manual removal or trimming, for instance. However, the process is time-demanding for large ponds. Additionally, manual removal will cause murkiness and stress pond creatures. You can also increase the salinity of the pond if you have no fish, using pond salt. The accurate ratio is 10 parts per thousands to kill cattails. However, it can also affect other, more desirable plants. 

A better option is to rely on a broad-spectrum product that can target cattails and other weeds, such as the Pond Logic Shoreline Defense, which works on a topical application basis. 


Removing pond sludge

Pond sludge is the result of rotting plants and organic waste that accumulate. It isn’t any type of weed per se, and therefore doesn’t require weed treatment. However, to remove pond sludge, you will need to find a clearing and dissolving solution, such as NaturalPond Muckstop, which is safe to use in fish ponds and harmless to aquatic vegetation. The pellets introduce good bacteria into the pond that consume the dirt. 


Follow up with a maintenance routine

Weeds that are removed can come back if you fail to adopt a pond maintenance routine. Keeping your pond healthy is more effective in the long term. A simple 3-step pond maintenance process would include the addition of beneficial bacteria to the pond, such as Muck Away, the use of supplements to support the presence of good bacteria, and the water oxygenation. Finally, you can also use a pond dye to filter UV lights and keep the temperature under control. 



For any questions about pond weed control or how to pick the right pond maintenance products, get in touch with our team, 215-525-1440.