Plants are far more than just a gorgeous addition to your backyard pond. They also serve a vital function in maintaining a suitable balance of nutrients from the pond’s water. Plants not only reduce the amount of algae which can grow, but in addition use waste substances from fish, offering a pure water filtration mechanism. Choosing the right combination of aquatic plants from the four categories will help keep your pond water clean and clear without the addition of chemicals.
Select plants which grow below the surface of the water. Submerged plants possess the largest contribution to water quality. They serve as oxygenators during daytime hours, supplying oxygen for fish, and they provide fish with excellent cover. Submerged plants compete with algae for use of nitrogen produced from fish waste and decaying plant material. Examples of underwater crops are hornwort (Ceratophyllum demersum), hardy in U.S. Department of Agriculture plant hardiness zones 5 through10; jungle val (Vallisneria americana), hardy in USDA zones 4 through 10; and cabomba (Cabomba caroliniana), growing in USDA zones 6 through 10.
Pot submerged plants in small containers full of gravel. The roots of these plants anchor the plant in position, but do not work in nutrient uptake. Potting of those plants allows for simple removal for loss or winterization.
Thin or eliminate underwater plants as required to reduce overgrowth within the pond.
Floating and Surface Plants
Pick plant species which grow flowers and leaves on the surface of the water. The difference between surface and floating plants is that floating plants float freely on the water’s surface with no attached roots, while surface plants have roots which stretch anchor and down into the pond’s dirt.
Maintain surface area coverage by surface and floating plants in approximately two-thirds coverage. These crops provide shade for fish and also limit the quantity of UV light necessary for algae to grow. Examples of floating crops comprise duckweed (Lemna minor), USDA zones 6 through10; sensitive plant (Mimosa pudica), USDA zones 9 through11; and water lettuce (Pistia stratiotes), USDA zones 9 through 10. Examples of surface plants are water hawthorne (Aponogeton distachyos), USDA zones 6 through 9; variegated four-leaf water clover (Marsilea mutica), USDA zones 5 through10; and water lotus (Nelumbo lutea), USDA zones 4 through 10.
Eliminate plants in case coverage exceeds two-thirds of this pond’s surface area. An excessive amount of coverage can inhibit the photosynthesis actions of this underwater, oxygenating plants.
Choose plants which grow well in always moist or soggy soils or that grow well in water. A few examples of marginal plants are western blue flag iris (Iris missouriensis), USDA zones 3 through 8; sweet flag (Acorus calamus), USDA zones 7 through 10; and dwarf bamboo (Sasa pygmaea), growing in USDA zones 6 through10.
Plant plants along the outer edge of your pond. The roots of these plants attach into the muddy dirt as well as the leaf grows over the pond’s surface. These crops compete with algae for available nitrogen in the water.
Avoid selecting marginal plants which spread rapidly or are invasive, like cattails.