Duckweed makes our list of worst water weeds because it can be a huge nuisance to ponds and other still water bodies. There are many different species of this flowering floating aquatic plant, most of which are native, but at least one of which is exotic. What they all have in common, however, is that with the right conditions, they can become incredibly invasive and wreak havoc on other native species. And yes, it also makes the list of 79 different invasive and exotic aquatic plants maintained by the Center for Invasive Species and Ecosystem Health. While ducks do love to feed on it, this water weed can rapidly outstrip the appetite of local waterfowl and take over a pond.

An infestation of giant duckweed
  • Scientific Name(s): Lemna minor, Pirodela polyrhiza, Landoltia punctate (to name a few)
  • Origins: The common and giant varieties are both natives to North America while the dotted variety (Landoltia punctate) was originally found in Australia and South Asia but escaped from cultivation and has been carried all around the world.
  • Habitats: These tiny plants love nutrient-rich ponds and other still or extremely slow-moving bodies of water. If a pond has lots of dead organic matter at the bottom, this is what becomes a rich source of nutrients for duckweed. Surface runoff from agricultural operations can also result in a pond gaining more nutrients than it would normally have, making it vulnerable to an infestation.
  • Eco-Impacts: This water weed can single-handedly ruin an otherwise healthy pond. When a relatively stagnant body of water becomes nutrient-saturated, duckweed takes off and can form a dense mat of vegetation on the water’s surface. It can rob the water of its oxygen, leading to fish die-offs, and can also crowd out other desirable native plant species such as sawgrass.

Correctly Identifying Duckweed

Common duckweed

Common duckweed (Lemna minor) is a floating freshwater aquatic plant featuring one, two or three leaves, with each having a single root hanging in the water. The plants can divide rapidly as more leaves grow and become separate individuals. The roots tend to be 1–2 centimeters long. The leaves are oval-shaped, typically 1–8 millimeters long and 0.6–5 millimeters wide, light green, usually with three (rarely five) veins and small air spaces for flotation assistance.

Giant duckweed

Giant duckweed (Spirodela polyrhiza) typically has two or three rounded leaves that are most often connected and sometimes feature a red dot on top. Giant duckweed usually has several roots (as many as nine) hanging underneath each leaf. The under-leaf surface of this species is dark red.

Dotted duckweed

Dotted duckweed (Landoltia punctate) is often confused with giant duckweed, but dotted duckweed is smaller, more shoe-shaped, and does not have a red dot on top. It typically features fewer roots (up to 4), and sometimes has a red margin on the underneath of the leaves. The “dotted” part of its name refers to barely perceptible raised dots on the surface of its leaves.

Duckweed Removal with Weedoo Environmental Work Boats


Controlling duckweed includes the physical removal. If you have a windy day, removal can be easier because the wind can push the plants to edges of the water body. Physical control of duckweed can be accomplished raking the plants off of the pond, but be sure to transport the harvested plants far enough away from the water body for disposal so that wind and runoff can’t transport them back to the pond.


Consider a Weedoo Work Boat such as our TC 3000 series or AquaHarvester.

The TC 3000 series features a Fiberglass/Kevlar® hull configuration with deck-mounted marine boom cutter, front-end loader with universal marine bucket system, and 1305 highway transportation trailer with emergency and safety tow kits. A factory-installed PowerPack features fluid cooled gas or diesel engine options with electric start. The VVR hydraulic reservoir provides eco-friendly fluid to a high-efficiency triple-pump setup producing 27 GPM. It includes twin propulsion outdrives with Weedoo Weed-N-Mud propellers and quick change hydraulics for Weedoo aquatic work attachments.

The AquaHarvester features Fiberglass/Kevlar® construction and includes the Weedoo 170-Conveyor/Harvesting System with detachable bag collection assembly and Weedoo T-1305 DOT-approved highway boat trailer. There is a factory-installed 24-Volt PowerPack including a lithium/solar battery system that runs all day without fossil fuel with an on-board marine charger and captain helm assembly. Available in single motor or twin Torqeedo outdrives mounted on Weedoo Power Trim-N-Tilt system.

Ready to tackle those pesky water weeds without chemicals? Contact Weedoo today!