Simple plants lacking a stem or leaves with a small root dangling below the surface. About the size of rice they reproduce very quickly by budding. They will quickly cover the surface of quiet waters and often drift as the wind blows.

Spread easily between water bodies from transport by wildlife or water movement. Higher in protein than soybeans, they are eaten by humans and waterfowl. Its ability to cover the surface entirely provides shelter for fish fry, turtles and frogs.

Oxygen depletion often results when the surface is covered and sunlight blocked out. Early treatment is recommended. Effective duckweed control can be expensive.