Many plants are referred to as water lilies but there are only two true families of water lilies. Lotuses are also called water lilies but belong in their own family. Nymphaeaceae and Menyanthaceae are the true water lily families. There are many hybrids today from each family. Water lilies can be seen growing naturally in lakes and ponds, or they can be used in water gardens.
The Nymphaeaceae family is very closely related to the magnolia because the flowers look very similar. The genus Nymphaea has about 40 different species. The species are divided into hardy and tropical. Hardy water lilies bloom May through October, while tropical lilies bloom July through August. The leaves float on the water and are almost completely circular. The leaf color above water is green and under water it is red. The diameter of the leaf is about 1 inch and the leaf has a round tip on the stem where the flower grows. The flower stems come up out of the water from the base of the plant. The height depends on how far down the base of the lily reaches. In nature, the lily can flower repeatedly. In the confines of a water garden, it may only flower four to six blooms. The flower color depends on the different hybrids.
The Menyanthaceae family is more diverse, with some species growing in wetland habitats to species that grow underwater with floating leaves and flowers above water. Plants with leaves that float have submerged roots and use the water to support their plant bodies. This family has many branched stems from where the flowers develop in clusters. The differences in the branched stem forms can be put into three categories depending on the number of flowers. The first type has two opposite leaves and one cluster of flowers, the second type has two leaves and two flowers, and the third type has one floating leaf supporting a compact cluster of flowers. The flowers in this family have fused petals that are tube shaped. The flowers are usually yellow or white with a few exceptions of pink or purple.
The Nymphaea odorata is a popular hybrid of the Nymphaeaceae family. It is commonly referred to as the white water lily or fragrant water lily. It is a perennial with round leaves that are a bright green with a split 1/3-inch long on the leaf. The leaves float on the water, while the sweet-smelling flower emerges from a separate stem. They open in the morning and close in the afternoon.
Water lilies that grow naturally can provide benefits for other parts of nature. The underwater part of the plant can provide a home for many micro and macro invertebrates. These small creatures become food for fish, reptiles and ducks. Once the plant dies and decomposes, the bacteria become food for other microorganisms. The leaves are eaten by deer, beaver and muskrat.
Water can become a focal point with the addition of a water garden. Water lilies are a natural choice in plant selection. Water gardens can contain floating plants, submerged plants or deep-water plants. Hardy lilies such as from the Nymphaeaceae family make good deep-water plants. Water lilies can be planted in pockets of soil on the bottom of the container. As water garden plants, aquatic plants require fertilizer when planted and again during the growing season. Aquatic plant fertilizers are either liquid, tablets or granular. The water lily provides great contrast, height and color in the garden.