Plants for Water Fountain Gardening

Fountains add movement and sound to a water garden and provide the humid conditions in which many kinds of water plants thrive. The four main kinds of aquatic plants are marginal, deep-water, submerged and floating plants. Including all these plant types in your water fountain garden will provide a range of heights, colors and shapes, and help keep the water clean and clear. Like other garden plants, aquatic plants grow best within their recommended U.S. Department of Agriculture plant hardiness zones, and they can spread rapidly. So take care not to contaminate rivers, lakes or streams with plant debris from your water garden.

Marginal aquatic plants grow in a few inches of water at the edges of a pond, and spray from a fountain keeps their leaves wet and shiny. Two examples of marginal aquatic plants are marsh marigold (Caltha palustris) and scarlet rose mallow, also called swamp hibiscus (Hibiscus coccineus). Marsh marigold grows 12 to 18 inches tall and wide, and it features yellow flowers from spring through early summer. Hardy in USDA zones 3 through 7, marsh marigold blooms best in a full-sun site but needs some shade in a hot-summer climate to prevent dormancy. Scarlet rose mallow is perennial in USDA zones 6 through 9 and bears bright, scarlet-red, 3- to 5-inch-wide flowers from midsummer through early fall. The plant grows 3 to 6 feet tall and 2 to 3 feet wide and thrives in full sun or partial shade.

Some deep-water plants don't grow well near the spray and water movement from a fountain but are grown for their leaves, which produce shade and so reduce algae, and for their flowers. Growing in 6- to 24-inch-deep water, sacred lotus (Nelumbo nucifera) features stems that reach 3 to 6 feet tall and rise out of the water. Sacred lotus grows 3 to 4 feet wide, and its large, fragrant, cup-shaped, pink or white flowers appear in summer. Another deep-water plant is the hardy water lily cultivar "Marliacea Chromatella" (Nymphaea "Marliacea Chromatella"); it grows best in water 12 to 48 inches deep. Its leaves and stems rise 3 to 6 inches above the water, and the plant spreads 5 to 6 feet wide. "Marliacea Chromatella" bears large, semi-double, cup-shaped, yellow blooms from late spring to the first frost. Scared lotus and "Marliacea Chromatella" are perennial in USDA zones 4 through 10.

A fountain adds oxygen to a pond's water, but the pond also needs submerged plants for the days the fountain pump is off because they also add oxygen and help keep the water fresh. Submerged plants include Canadian pondweed (Elodea canadensis) and hornwort, which also is called coon's tail (Ceratophyllum demersum). Canadian pondweed has tangled, dense, 3 1/2-inch-long stems covered with dark-green leaves. From mid- to late summer, tiny, greenish-white flowers appear on the plant, but it usually is grown for its ability to absorb nutrients and reduce algal growth instead of for its flowers. Canadian pondweed is hardy in USDA zones 4 through 10 and grows best in a full-sun site. Hornwort, hardy in USDA zones 7 through 10, grows up to 3 feet 3 inches long, its stems encircled by whorls of fine leaves. Hornwort grows in full sun and partial shade.

Plants that float on their pond's water surface shade the water, reducing algae problems. Two species called water fern are among the floating plants that provide shade. The water fern species Azolla filiculoides, hardy in USDA zones 7 through 10, produces mats of mosslike foliage 1/2 inch tall. In still water exposed to full sun or partial shade, the foliage grows so thick that it is believed to prevent mosquitoes from breeding, which earned the plant its other common name, mosquito fern. The water fern species Ceratopteris pteridioides produces deeply cut fronds up to 16 inches long. Its fertile fronds stand more erect than its sterile fronds, which grow about one-half as long as the fertile fronds. Also called floating fern, Ceratopteris pteridioides is perennial in USDA zones 9 through 11 and requires full shade or partial shade. Throw both kinds of water ferns in your pond, and they will naturally travel to areas where the water is undisturbed by the fountain.