Many varieties are tropical and must be treated as annuals, but there are also a large number of hardy varieties. In garden pools, water lilies are grown in containers of topsoil that set on the pool bottom. Pebbles on the surface of the container help to prevent the dirt from clouding the water. The spectacular lotus is also a well known water flower. Leaves may measure two feet across.
Blossoms are huge, very fragrant and rise several feet out of the water, creating quite a show.
Miniature cultivars are more suitable for small ponds. Marginal plants are a category of plants that grow in the boggy ground or shallow water at the edges of the pond. They are characterized by roots that grow in the soil. Examples include cattails, Chinese water chestnut, horsetail grass, marsh marigold, pickerel rush and several varieties of iris. Their leaves and flowers literally float on the pond surface while roots hang into the water.