Can I keep my plants in the pond during the winter?

That depends on which plants you are growing. Some aquatic plants are perfectly hardy and can spend the winter in the pond. Hardy water lilies and lotus can simply be moved to a lower depth in the pond. Hardy plants such as cattails, water iris, and rushes can stay near the water's surface where they normally grow. Tropical plants such as tropical water lilies, cannas, and papyrus cannot even tolerate cold water, so they must be kept in a greenhouse over the winter or they must be started from new divisions every year.