Aquatic plants aren’t just used in the water garden to provide beauty and naturalization – they also serve the very important function of helping to balance the pond ecosystem. Their valuable biological filtration helps remove nitrogen, ammonia, nitrates, and other minerals that algae would otherwise feed on. In addition, the plants provide food, shade, and protection for the fish and wildlife that live in and around the pond. Typically, they are divided into four groups – water lilies, marginals, floating plants, and submerged plants.
Water lilies are available in hardy and tropical varieties. They both come in a wide variety of colors, shapes, and sizes and the leaves provide fish with shade from the heat of the summer sun, cooling the water and making algae control easier too.
Hardy water lilies are reliably perennial from the northern reaches of Zone 3, to the subtropical areas of Zone 11. The white, pink, red, or yellow flowers float directly on the water surface and are open during the day. When cold weather comes, the foliage dies. This should be removed before winter. New leaves emerge again in the spring.
The flowers of tropical water lilies sit above the water and come in the typical whites, yellows, pinks, and reds. Unique to tropical water lilies are the blue shades - light blue to deep purple. Flowers are also more often fragrant and there are varieties available that bloom at night.
Although tropical lilies are only hardy to zones 10 and 11, they can be planted in colder zones when the water temperature is consistently above 70º F and treated as annuals or over-wintered, if given proper care.
To Pot or Not?
Go natural when planting your water lilies – hide those pots! Planting pockets help you do this. Hopefully these have been excavated into your pond, if not, you can create them with rocks right on the liner. Place the potted lily into the pocket and cover with rocks to hide the pots.
Fertilizing water lilies is necessary to encourage a greater number of larger flowers. Time-released, granular fertilizer, mixed into the soil at the bottom of the pot or plant pocket is a great way to fertilize lilies at the time of planting. Any other time, however, it would be messy and inconvenient. That’s when lily fertilizer tablets work great.