Lemna minor (Common Duckweed)

Among the smallest of the flowering plants, Lemna minor (Common Duckweed) is a free-floating, aquatic perennial forming a carpet of tiny, oval-rounded, bright green leaves. Each plant consists of a single flat leaf with a single hanging rootlet. Tiny white flowers are rarely produced. Common Duckweed notoriously multiplies and creates dense colonies that are an important food source for ducks, waterfowl, muskrats, beavers, birds, fish and frogs. It can stop the proliferation of mosquito larvae and helps remove pollutants (phosphorus and nitrogen) from the water. But, it can also become a nuisance. If it covers the surface of the water, then oxygen depletion and fish kills can occur. It will also eliminate submerged plants by blocking sunlight penetration. This plant should be controlled before it covers the entire surface of the pond. Native throughout most of the world, Common Duckweed occurs naturally in freshwater ponds and slow-moving streams. It grows extremely quickly under optimum conditions. In temperate regions, when temperatures drop below 42-44°F (6-7°C), small, dense organs called ‘turions’ are produced. The plants then become dormant and sink to the ground for overwintering. The following spring, they restart growing again and float back to the surface. Common Duckweed is a popular addition to water gardens and ponds, where it provides attractive foliage cover and discourages algae growth.

• This deciduous perennial grows up to 2-3 in. tall (5-7 cm) and 12-36 in. wide (30-90 cm). 
• Performs best in full sun to part shade on still water in water gardens, ponds or aquatic containers.
• Virtually pest and disease free.
• Reduce its spread by removing portions with a net.
• Native throughout most of Africa, Asia, Europe and North America.
• Can be quite invasive in frost-free climates. Find where this species is invasive in the U.S.