Watermeal

Description

Watermeal is a very tiny, light green, free-floating plant that resembles specks of cornmeal. In fact, Watermeal is the smallest seed-bearing plant in the world. Watermeal tends to grow in dense colonies in quiet, undisturbed water. Often Watermeal will be associated with colonies of duckweeds. Watermeal can be an aggressive invader of ponds and are often found mixed in with duckweeds or mosquito fern. If colonies cover the surface of the water, then oxygen depletion and fish kills can occur. These plants should be controlled before they cover the entire surface of the pond.


Other Names: Wolffia

Mechanical Control

Watermeal can be controlled by raking or skimming it off the pond's surface. This can rather difficult due to the small size of watermeal.


Watermeal typically prefers stagnant and slow moving water. By adding an aeration system, you can eliminate Watermeal completely or limit the growth to the edges which are easily reachable with a net.

Chemical Control

Broad spectrum contact herbicides, such as Ultra PondWeed Defense® or Clipper, will quickly kill any part of the plant it touches but multiple treatments may be needed throughout the season.

Chemical Application Best Practices

Anytime you use chemicals treat weeds or algae, please keep in mind the following:

  • Treat your pond in sections. Treat only half the pond's surface at a time. During hot weather or when treating heavy growth, it is important to treat no more than ¼ of your pond at a time and wait the full 14 days before re-applying. This helps lower the risk of fish loss during hot weather or when treating heavy growth.
  • Once the weeds have browned, use a rake to remove as much dead material as possible. This prevents an accumulation of dead plant material and muck.
  • Take a proactive approach to pond management. Use PondClear, MuckAway and Pond Dye to keep your pond looking great. For more information, see our article on the Airmax® Ecosystem

Ask an Expert

If you are unable to identify your pond weed(s) using our Weed ID Guide, follow this article to email us a photo.

  • List | Grid

Products

  • Pond Logic® Ultra PondWeed Defense® Aquatic Herbicide

    Pond Logic® Ultra PondWeed Defense® Aquatic Herbicide

    Review star icon Review star icon Review star icon Review star icon Review star icon
    Broad Spectrum Pondweed Control Fast Acting Liquid Formula Short Term Control Of Duckweed Pond Logic ® Ultra Pondweed Defense ® works on pond weeds including submerged, floating and emergent weeds. This pond herbicide may be used for short...
    Read More »
    $39.99–$119.99
  • Valent® Clipper™ Aquatic Herbicide

    Valent® Clipper Aquatic Herbicide

    Review star icon Review star icon Review star icon Review star icon Review star icon
    Fast & Selective Control Of Weeds Treats Floating & Submerged Weeds Dissipates Quickly Through Water Column Valent ® Clipper ™ Aquatic Herbicide delivers fast and selective control of tough invasive and nuisance plants such as...
    Read More »
    $229.99–$899.99