Mature water plants are dazzling additions to any pond or water garden. While large plants are in need of seasonal care to ensure continued growth and survival throughout the year, annual care is also needed to maintain healthy plant growth and regulate invasiveness. After all, large aquatic plants are only beautiful if they are well-maintained.
During the course of every season, continued care is necessary with pond plants. Spring brings the need to re-establish plants in the pond and see to any additional propagation that was not tended to the previous fall. Summer is the time for growth, but maintaining plant invasiveness is of particular concern. Fall is a great time to propagate overgrown plants and cut back foliage to overwinter. Winter, of course, is when plants are allowed to go dormant either on the pond floor or in a dark storage space that does not freeze.
Once every year, either in spring or fall, water plants should be repotted. Aquatic plants have a tendency to grow very rapidly and some may need transplanting both in the spring and fall. Propagation can occur simultaneously when transplanting, especially if the plant is overgrown. Overgrown plants are not only displeasing aesthetically, but they can starve the pond of nutrients and sunlight and kill off other aquatic life.
Propagation of water plants is divided into two methods: vegetative and sexual. Vegetative propagation is the easiest method when dealing with aquatic plants; it usually consists of stem cuttings or tuber reproduction. Sexual or seed propagation is forming a new plant from a seed or spore. Few plants propagate successfully from seed reproduction in aquatic gardening, although the Cyperus family is an exception and tends to germinate quite readily.
Propagation by division simply divides the rhizome and replants the separate plants in containers to regrow. Water plant rhizomes come in all shapes and sizes, from the thick rhizomes of the water lily to the creeping rhizome of watercress. Divisions of creeping rhizomes and other small varieties should contain a section of the horizontal rhizome and a vertical shoot. The shoot and the buds found on water lily and lotus rhizomes need to be exposed above the soil level when planting to generate new growth.
Using a section of plant to generate an entire new plant is propagation by cutting. Generally, a section of stem, three nodes in length and bearing a small bud on one end, is cut and planted. Oxygenating plants like anacharis and parrot's feather are great plants to propagate this way. Other water plants, like lizard's tail, only need a single leaf cutting to stimulate new root growth. One leaf with a stem intact has the ability to generate an entire new plant in this form of propagation.
Aquatic plants like tropical water lilies and taro often shoot tubers out from the soil at the base of their leaves. When left, these tubers can produce foliage or mini-plants that will soon die if not placed in a planting medium. When cut, these tubers can be trimmed and planted with the growing end exposed to generate a new plant. Once roots form, the new plant can be removed and potted in separate containers.