Floating pond plants float on the water surface and do not need a pot or container to grow.
While other aquatic plants have certain planting requirements floating plants do not, just add water and full sun and they will flourish. But this characteristic, if left unchecked will allow floating plants to completely cover a ponds surface.
Some states have placed a ban or restriction on these plants in an effort to control them. You should never introduce any aquatic plants into your local environment.
While they may benefit your pond, in an uncontrolled environment it is possible that they can become nuisance plants.
Floating plants shade the pond surface which is very beneficial in sunny weather.
They limit sunlight which will keep algae in check and will keep the water temperature down as well.
Submerged plants also require a little shade to do well, with out some shade they can become sun burned and perform poorly.
Shade is important for your fish also and provides a place for them to hide under when hungry herons or raccoons drop by.
Their roots hang below the plant, feeding off the nutrients in the water, starving algae of nutrients. So floating plants go a long way in preventing an algae bloom by, controlling sunlight, water temperature, and robbing algae of nutrients.
Fish feed off the roots too so not only do these plants provide shade, or a hiding place but also are a good food source for fish.
The roots that can hang below the plant by 2 to 4 inches and will also act as a natural biological filter.
Most pond owners believe in placing floating plants in flowing water to assist in filtering which will reduce the load on the bio-filter.
The most common placement is at the head of a waterfall or in a stream bed and is illustrated in the photos on this page. The only requirement is that you contain the plants in some way so that the flowing water will not carry then away.
The photo of the waterfall shows that this pond owner used a plastic plant carrying tray to contain the plants. While the photo of the stream bed shows the plants being contained by rocks.
Floating pond plants when used this way will not only enhance the look of the pond but add extra filtering ability.
They can be quite attractive especially when in full bloom but also soften the edge of a stream or waterfall with visual interest.
Another benefit of floating plants is that they provide some oxygen as well. They may not be a true oxygenator like a submerged plant is but they do introduce some oxygen into the water.