Water Gardens – Annual Aquatic Plants
Floating plants are a necessary addition to any home water garden. They are easy to introduce, as they do not require any soil. They simply grow by floating on the water surface. They help control algae naturally in two major ways. First, their long suspended root systems utilize the dissolved nutrients in the water, diminishing nourishment for the algae. Second, they provide shade as they multiply; reducing the required sunlight algae needs to grow. Floating plants also provide good homes to goldfish eggs and young in their long roots. Although floaters are usually treated as annuals in Canadian water gardens, it is often advantageous to overwinter them indoors. With a little room and effort, you can save on cost and enjoy the benefits of a much larger plant the next season!
• Water Hyacinth (Eichhornia crassipes major) is a tropical floating plant that performs best in full sun and warm shallow water (Zone 9). Although often treated as an annual in our climate, they may be overwintered if the conditions are right.
• At the end of each growing season, before the first frost, the water hyacinth can be moved indoors to spend the winter. Once indoors, the plant requires a source of warm shallow water (around 20°C), as well as a bright sunny location.
• An indoor aquarium positioned next to a sunny window is an ideal place. If available, they could greatly benefit from an added grow light. Wide spectrum aquarium light bulbs can be purchased at any pet store.
• The aquarium should be cleaned regularly. Change the aquarium water monthly and wipe off any algae that develop on the glass surface.
• The plants can then be returned to the outdoor pond next summer after all danger of frost has past (June 21st ). If lucky, these larger, more mature plants may produce their enchanting orchid-like violet blooms.
• Water lettuce (Pistia stratiotes), is another annual floater that can be overwintered in an indoor aquarium. It is a floating plant with velvety blue-green leaves which form into a rosette (Zone 9). It has long trailing roots similar to the water hyacinth. When trying to overwinter your water lettuce the same steps should be taken as for the water hyacinth.