Duckweed

Description

Duckweed is a very small floating plant. It has shoe-sole shaped leaves with a small hair-like root hanging below. It resembles a four-leaf clover approximately the size of a pencil eraser. Duckweed in ponds is frequently misidentified as algae. Once established, duckweed in ponds can cover the entire water surface and resemble a golf course green. It can cut off sunlight to submersed plants and cut off oxygen to fish and other wildlife. If you need to begin duckweed control, read below.

Mechanical Control

One duckweed control method is by raking or skimming it off the pond's surface.


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

Chemical Control

There are several options to control duckweed in ponds.

  1. Use a season long herbicide such as Sonar A.S.. One treatment treats duckweed and many other common pond weeds for the season.
  2. Use a broad spectrum contact herbicide, such as Ultra PondWeed Defense®, will quickly kill duckweed. Because it does not stay in the water body, multiple treatments may be needed throughout the season.
  3. Use Clipper, a fast and selective herbicide that controls tough invasive and nuisance aquatic plants.

Chemical Application Best Practices

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

  • When beginning duckweed control, 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 »
    $49.99–$149.99
  • SePRO Sonar™ A.S. Aquatic Herbicide

    SePRO Sonar A.S. Aquatic Herbicide

    Review star icon Review star icon Review star icon Review star icon Review star icon
    Season Long Weed Control Treats Floating & Submerged Weeds Systemic Herbicide That Kills Roots Even the most persistent weeds don't stand a chance against Sonar™. SePRO Sonar™ A.S. Aquatic Herbicide can be used to control stubborn...
    Read More »
    $239.99–$2,399.99
  • 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
  • SePRO Sonar™ RTU - 1 Quart

    SePRO Sonar RTU - 1 Quart

    Review star icon Review star icon Review star icon Review star icon Review star icon
    Long Lasting Weed Control Effectively Treats Duckweed No Mixing - Easy To Apply Sonar ™ RTU is a Ready-To-Use formula that controls most troublesome pond weeds including Duckweed. No mixing, no need for spray equipment or a boat—simply...
    Read More »
    $99.99
    Qty.
  • SePRO Total Pond - Prevent®

    SePRO Total Pond - Prevent®

    Prevent & Control Weeds All Season Systemic Herbicide That Kills Roots Easy-To-Apply Granular Formulation SePro Total Pond - Prevent ® controls a wide variety of submerged and floating aquatic vegetation with a single treatment. Prevent...
    Read More »
    $84.99
    Qty.