Water lilies are a treasured addition to any pond, bringing vibrant colors and providing shade and shelter that supports the entire aquatic ecosystem. However, these floating plants often become a target for various animals, insects, and fish, leading to damage. Determining the source of the problem is the first step toward protecting your water lilies, and the key lies in examining the specific pattern of destruction left behind. The nature of the damage—whether it involves missing roots, shredded leaves, or just a few pinholes—can immediately point to the culprit.
Mammalian Pests Targeting Roots and Stems
Damage to water lilies is inflicted by larger mammals that target the submerged structure of the plant. Muskrats feed on the fleshy rhizomes and tubers, which serve as the plant’s food storage unit. An infestation often results in entire plants suddenly going missing, as the muskrat pulls the plant down to access the starchy root structure. Finding burrows or tunnels excavated into the bank near the waterline provides a clear sign of their presence.
Beavers also consume water lilies, especially the underground parts, and they often store the thick, starchy rhizomes for later consumption. While beavers are known for cutting down woody vegetation, they readily eat the leaves, flowers, and roots of aquatic plants. Evidence of beaver activity includes chew marks on nearby trees or thick stems. The sudden disappearance of multiple water lily plants, with the roots completely removed, suggests a large rodent is at work.
Waterfowl and Surface Grazers
Damage appearing on the water’s surface, involving the pads and flowers, is often caused by waterfowl like ducks, geese, and swans. Ducks and geese prefer the soft, tender new growth of the leaves and flower buds. This feeding leaves behind a distinctive pattern of clipped edges on the floating pads, appearing as if the edges have been neatly snipped off.
Swans are destructive because they eat the leaves and stems, and they use their long necks to pull up and consume the rhizomes in shallow water. Waterfowl also cause destruction by trampling and paddling through the plants. The presence of dense accumulations of droppings on the remaining pads or along the pond banks is a sign that these birds are responsible for the diminished foliage.
Insect and Aquatic Invertebrate Damage
Smaller, localized damage is caused by a variety of insects and aquatic invertebrates, each leaving a distinct feeding signature. Water lily aphids are small, dark-colored insects that cluster on the pads and flower buds. These sap-sucking pests drain nutrients from the plant, causing the leaves to prematurely yellow, curl, and wilt, which can halt new growth.
The water lily beetle and its larvae inflict harm by creating small holes that can progress to complete skeletonization of the leaf tissue. The adult beetle and its grub-like larvae feed on the leaf surface, leaving behind small, brown spots. Snails, such as the Great Pond Snail, also graze on the pads, leaving small, irregular holes and a visible translucent slime trail.
Fish can also be a factor, especially herbivorous species or those that disturb the bottom sediment. Grass carp, often stocked to control other aquatic weeds, readily eat the tender new shoots and flowers of water lilies when other food sources are scarce. Large koi can also be problematic, as their habit of rooting around the bottom of the pond can uproot newly planted water lilies or dislodge the tubers from their containers.