Free-floating plants are plants that are not anchored in the sediment; they get their nutrients directly from the water. Free-floating plants include the duckweeds, bladderwort, coontail, and the invasive water lettuce and water hyacinth.

Floating plants and floating-leaved plants perform many functions in waterbodies. Some of the most common are described below:

Role of floating plants and floating-leaved plants

• Provide food and habitat for wildlife and fish. Food for fish is provided principally when many varieties of small animals feed on the algae that have attached themselves to these plants.
• Can reduce shoreline erosion.
• Decaying material produced by floating-leaved plants accumulates in the sediments over many years playing an influential role in making a waterbody shallower.
• Debris from floating leaved plants contributes to the formation of peat deposits, particularly as the lake becomes shallower over time and aquatic plants grow more abundantly.
• If periods of low water are followed by a rapid rise in water level, the roots of some dead float-leaved plants (called rhizomes) can float to the surface where they block access and cause difficulties with navigation. In many cases, masses of rhizomes (especially from the native plant spatterdock) uprooted from the bottom can form floating islands called tussocks - becoming so large that trees can grow on them.
• In waterbodies where water hyacinth or water lettuce grow extremely well, these plants may completely cover the waterbody's surface and cause major habitat, recreational, navigational and flood control problems.

In Florida
Floating plants and floating-leaved plants occur in many Florida waterbodies. If the lake is shallow enough, rooted floating-leaved plants can grow completely across it. In Florida waterbodies where there are extensive loose sediments, the roots of floating-leaved plants anchored to the bottom provide a stable surface that some species of fish need for successful spawning.

The stems of floating-leaved plants (i.e. spatterdock) often contain burrowing insects called bonnet worms that some anglers use for bait. In many Florida waterbodies, certain floating-leaved plants are considered a major aquatic weed problem and require constant management in order to maintain acceptably low levels. For example, water hyacinth can grow so densely that waterways become impassable.

Health Concerns
Floating plants and floating-leaved plants are not generally thought of as a human health concern, although they can create problematic situations. For example, the floating plant water lettuce provides habitat for certain species of mosquitoes.