Plants in a water garden need to be kept wet at all times. Some plants prefer the edges of water gardens, while others grow in the water. Most water plants have large leaves and brightly colored flowers. Some have only foliage, or foliage with inconsequential flowers (the flowers are not large enough to be noticed, or they are green).
The waterlily (Nymphaea) has several different cultivars. Each cultivar has its own look--the flowers and leaves are different. Waterlilies thrive in USDA hardiness zone 3 and grow to a height of 6 inches. They prefer water to a depth of 18 to 24 inches and bloom in May through September. They grow in clumps. Cultivars that seed spread and may become invasive. To control the growth of waterlilies, choose non-seeding cultivars. The waterlily provides food for mammals and wildfowl.
The lizard's tail (Saururus cernuus) is so-named because of its long, arching floral spikes. The spikes, or fruit of the plant, turn brown when they mature, resembling a lizard's tail. The perennial plants grow in clumps and reproduce via runners. The lizard's tail is a good water feature, as it adapts to many different pH levels, making it low maintenance. It grows up to 2 feet in height. The leaves are shaped like an arrowhead and grow up to 6 inches long. The spikelike flowers are white and bloom from June through September. It prefers shallow water or the shores of swamps and lakes.
The common rush (Juncus effusus) grows up to 48 inches in height and 24 inches wide. It has a moderate growth rate, so it spreads rapidly via rhizomes (underground stems). The foliage is hollow, and the flowers are small, yellow blooms that appear in the summer. It grows in USDA hardiness zones 4 through 9 in 3 to 5 inches of water. It prefers an acidic environment and a sunny area. The common rush is used in pond landscapes and in water containers. When grown in the wild or near water features, it provides cover for several birds.