Floating plants add visual interest to ponds or water gardens in terms of color, texture or flowers. They are also ideal because they help reduce water loss through evaporation and help maintain water quality. These plants develop extensive root systems that filter dissolved mineral salts and other nutrients directly from the water and are often used as part of an algae-control regimen. They also provide shade to further curb aggressive algae growth. Finally, floating plants provide habitat for a wide variety of vertebrate and invertebrate animals and provide food for waterfowl, fish and mammals.

Floating plants can be divided into three categories:

Free Floating - These plants float freely on the water surface. The entire plant is suspended on the water, allowing it to be moved around the pond by wind and water currents. Since these have no roots anchored in soil, they draw 100 percent of their nutrients directly from the water, feeding on nutrients that would otherwise feed algae.

Submersed Floating-leaved - These plants are anchored by roots to the bottom of the pond, but their leaves and flowers grow to and float on the water surface. 

Trailing Floating - These plants are rooted into the shallow areas nearest the bank and have a trailing or creeping growth habit which allows them to form floating mats that extend out over the water surface. 

It should be noted that most floating plants have very fast growth rates. They have the potential to create a barrier on the water surface that prevents oxygen exchange with the atmosphere and photosynthesis in the water. As a result, uncontrolled growth of floating plants will reduce oxygen in the water and increase the potential for a fish kill.

Caring for free-floating plants is very simple. Since there is no root system, it is a matter of simply netting out their excess to allow other plants to grow below them. Do not throw the excess plants into any natural body of water. They could easily take over the pond and smother native plants and wildlife.

Because of their aggressive nature, it is important to ensure that the floating plants you use in your pond or water garden are not invasive and are safe to grow in your location. Please contact your local department of fish and wildlife for more information on invasive species in your area.