Water lilies are an iconic presence in water gardens and ponds, celebrated for their serene beauty. These aquatic plants float on the water’s surface, creating a tranquil atmosphere that has been admired for centuries. Their cultural significance is notable, famously captured in the impressionist paintings of Claude Monet. Their presence in a body of water signifies a calm environment, appealing to gardeners and nature enthusiasts.
The Anatomy of a Water Lily
A water lily’s structure consists of three primary parts: the rhizome, the pads, and the flower. The rhizome is a thick, fleshy stem that anchors the plant in the mud at the bottom of the pond. It functions as a storage organ for nutrients, allowing the plant to survive through dormant periods. From this base, long stems extend upwards, supporting the leaves and flowers.
The leaves, often called lily pads, are the most recognizable feature. These round leaves float flat on the water’s surface. A waxy coating on the top of the pad repels water, and a distinct notch helps drain excess water off the leaf. Often confused with lotus plants, water lilies are distinct; their pads float directly on the water, while lotus leaves rise high above it on rigid stems.
The flowers of the water lily are symmetrical and star-shaped, resting on or just above the water. These blossoms display a daily cycle, opening in the morning and closing in the late afternoon. Unlike the lotus flower, which has a prominent, cone-shaped seed pod in its center, the water lily’s reproductive parts are less conspicuous, nestled within the petals. This difference is a clear way to distinguish between the two plants.
Hardy and Tropical Varieties
Water lilies are categorized into two main types: hardy and tropical. Hardy water lilies are perennials capable of surviving cold winters, provided their rhizomes are planted below the ice line in a pond. Their flowers float directly on the water’s surface and are known for their softer, pastel colors, including pink, yellow, and white. Some hardy varieties are “changeable,” meaning their flower color can shift from yellow to a rosy peach over their blooming period. The pads of hardy lilies are thick with smooth edges.
Tropical water lilies, in contrast, thrive in warmer water and must be treated as annuals or stored indoors over winter in colder climates. They offer a more dramatic and vibrant color palette, including intense blues, purples, and fuchsias not found in hardy types. The flowers of tropical lilies are often larger and held on stems that stand several inches above the water’s surface. Their pads can also be more decorative, featuring mottled patterns or serrated edges.
A significant distinction is their blooming schedule. While all hardy lilies are day-bloomers, tropicals can be either day-blooming or night-blooming. Night-blooming varieties open in the late afternoon or evening and close by mid-morning the next day. This offers a unique display for those who enjoy their ponds after the workday.
The Water Lily’s Role in a Pond Ecosystem
Beyond its aesthetic value, the water lily contributes to the health of its aquatic environment. The broad, floating leaves provide extensive shade across the pond’s surface. This shading helps keep the water cooler during hot summer months and, by blocking sunlight, limits the growth of algae. Clearer water with less algae improves the overall health of the pond.
The plant’s structure also offers benefits to wildlife. The lily pads create a protective cover for fish and amphibians, shielding them from aerial predators like herons and other birds. Under the surface, the intricate root systems and stems provide a safe habitat for smaller aquatic insects and fish. This shelter is a component of a balanced ecosystem.
Water lilies also act as natural filters for the pond. Through a process called phytoremediation, their roots absorb excess nutrients like nitrogen and phosphorus from the water. These are the same nutrients that can fuel algae blooms if left unchecked. By taking up these substances, water lilies help maintain water clarity and quality.
How to Plant and Care for Water Lilies
Successful cultivation of water lilies begins with proper planting. They are best grown in aquatic baskets or large containers without drainage holes to control their spread. The ideal soil is a heavy loam or a formulated aquatic potting mix, as standard potting soils are too light and will float away. For hardy types, the rhizome should be planted at a 45-degree angle, while tropical tubers are placed vertically in the pot with the growing tip just above the soil surface.
Once the rhizome is positioned, the soil should be covered with a layer of pea gravel or small rocks. This top layer prevents the soil from clouding the pond water and stops fish from disturbing the plant’s roots. Water lilies require a location with at least six hours of direct sunlight per day and calm, still water away from fountains or waterfalls.
After planting, the container should be slowly lowered into the pond. Initially, position the pot on bricks so the top sits about 10-15 cm below the surface. As the plant grows and sends leaves to the surface, the pot can be gradually lowered to its final depth. Regular maintenance includes fertilizing with aquatic plant tabs and trimming away any yellowing leaves or spent flowers to encourage new growth.