Watermeal Control in Ponds


Dense infestations of watermeal are not just unsightly, but they can sharply reduce the amount of sunlight entering the water column causing a reduction of photosynthesis among all submerged pants. Watermeal's tendency to cover entire surfaces of water also reduces the oxygen levels of the water body resulting in oxygen depletion that can kill fish and other organisms. Watermeal is typically spread by clinging to the feathers of waterfowl going from pond to pond.

Watermeal’s small size makes it very tough to control. Watermeal has a very thick cuticle on both sides of plant that makes it tough for herbicide to penetrate. Its small surface area also means that there is significantly less area for effective herbicide contact and uptake. Herbicide is also easily washed off with any water movement near the plants. Repeat applications are a must since watermeal multiplies so fast (watermeal populations can double in only two days).

We recommend that you treat for watermeal as soon as it appears. For the herbicide to have the greatest effect of the watermeal, it is best to apply it before the watermeal has completely covered the pond's surface. It is a good idea to take regular walks around the pond looking for signs of watermeal colonies.

Manual removal (such as scooping it out with a net) of watermeal is often ineffective because if even just a small fraction of the watermeal is not removed, it will quickly propagate and you'll be back out there scooping up the watermeal again in no time. Because of watermeal's explosive growth pattern, we recommend herbicidal treatments for optimum results.  Clipper is the most effective herbicide for controling watermeal, it also treats a variety of algae and and submerged weeds. 

Because watermeal thrives (and can easily reproduce explosively) in waters with high phosphorus levels, part of your control method should concentrate on reducing the water body's nutrients, especially Phosphorus. PhosControl® is one such product capable of doing this.

We recommend using our Watermeal POND Solution products for watermeal  control  and to help prevent future outbreaks.

If you have any questions or would like to speak to us about watermeal control, please feel free to call us at: 1-877-428-8898

Watermeal Identification


Wolffia spp.

Watermeal is small in size and is a free-floating granular plant. It is the world’s smallest flowering plant and resembles small grains of green cornmeal. Watermeal can be mistaken for algae or duckweed. One way to differentiate it from duckweed is that watermeal lacks roots.

When present, it is usually abundant and often covers the entire surface of the water. Usually it grows in quiet waters with no wave action. Watermeal is also often found mixed in with other duckweed species.