When composing a water garden, remember it is an ecological system, said Charles Thomas, president of Lilypons Water Gardens in Lilypons, Md. "The important thing is to have the right elements." Here are some:
Water lilies not only provide beauty to the pond, but the lily pads create shade and reduce algae, he said. Scavengers, such as snails, are also helpful in reducing algae. "I especially like the black Japanese snail (Viviparus malleatus). It won't come out of the water, it won't overpopulate the pond and it won't eat the plants." One black Japanese snail per every 1 to 2 square feet of pond surface area should do the job, Thomas said.
Fish are another practical addition to the pond, according to Thomas. "They keep the pond from becoming a mosquito factory. Most people use goldfish (Carassius auratus). " The comet goldfish and the Japanese fantail are two popular pond additions, he said.
Pond water will naturally keep clear with the addition of submerged plants such as waterweed (Elodea canadensis)-- a fernlike plant with tiny white flowers--and Washington grass (Cabomba caroliniana). Sold as cuttings in bunches of six, submerged plants are planted by pressing their stems into a bucket topped with a thin layer of gravel. The plants are then placed at the pond bottom. Use one submerged plant bunch for every 1 to 2 square feet of pond surface area, recommended Thomas. "These are secret water cleaners. They feed through their foliage, drawing nutrients from the water."