A healthy ecosystem pond should contain a combination of water lilies, marginal plants, floating plants, and submerged plants (oxygenators). Each type serves a different purpose, helping improve water quality, absorb excess nutrients, provide shade, and create a natural habitat for fish.
1. Water lilies
Water lilies grow from the bottom of the pond and produce floating leaves and flowers at the surface.
Examples: Hardy water lilies and tropical water lilies.
Benefits: Provide shade, help reduce sunlight penetration, and offer shelter for fish.
Placement: Generally grow in water 12–36 in. (30–91 cm) deep, depending on the variety.
2. Marginal plants
Marginal plants grow in shallow water around the edges of the pond.
Examples: Water iris, pickerel plant, sweet flag, aquatic canna, and creeping Jenny.
Benefits: Absorb excess nutrients, provide natural filtration, and soften the appearance of pond edges.
Placement: Many varieties grow in approximately 2–6 in. (5–15 cm) of water. Requirements vary by species.
3. Floating plants
Floating plants rest on the water's surface with their roots hanging directly into the water.
Examples: Water lettuce and water hyacinth.
Benefits: Absorb nutrients directly from pond water, provide shade, and help limit algae growth.
Placement: Float freely on the pond surface without needing soil.
Note: Some floating plants are invasive or restricted in certain states. Check local regulations before purchasing or introducing them.
4. Submerged plants (oxygenators)
Submerged plants grow primarily beneath the water's surface.
Examples: Anacharis, hornwort, and cabomba.
Benefits: Absorb excess nutrients, produce oxygen during daylight hours, and provide hiding places for fish.
Placement: Grow underwater, with appropriate depth depending on the species.
Note: Submerged plants do not replace the need for proper pond aeration and circulation.
How do I choose the right plants?
For the best results:
Use a variety: Include plants from all four categories whenever possible.
Provide shade: Aim for approximately 40–60% of the pond surface to be covered or shaded by aquatic plants during the growing season.
Consider sunlight: Select plants suited to the amount of sunlight your pond receives.
Choose hardy or tropical varieties: Hardy plants are better suited to colder climates, while tropical plants may require winter protection or seasonal replacement.
Consider fish: Select plants that provide shelter and can withstand activity from koi or other pond fish.
Avoid overcrowding: Leave enough open water for circulation, surface gas exchange, and viewing fish.
A balanced combination of aquatic plants helps create a healthier, more attractive pond while naturally reducing excess nutrients that contribute to algae growth.