Although most pond plants in the UK are fully hardy, they are also mostly deciduous, so their top growth dies and turns brown in late autumn. In winter, the leaves will die back to the crown of the plant, back to where the leaf stems end and the roots begin. Overwintering pond plants, such as lily-like aquatic plants, should be submerged, but warm enough. A good idea is to immerse them in a large plastic tub in the greenhouse, in a warm area of the house, or use an aquarium heater.
Examples of these are the floating heart, mosaic, poppies and water buckthorn. There are very few pond plants in the UK that will continue to thrive in winter, and most will die until spring. However, plants such as Elodea Crispa and Hornwart are evergreen plants and will continue to grow throughout the year, providing much-needed oxygen during the colder months. Plants such as water lilies should be pruned to their lowest point so that they can resume their growth process in the spring.
Most pond plants remain dormant in winter and top growth disappears as do perennials that grow in the ground. It's a good idea to trim, the tips are back just above the crown in late fall and remove the cuttings from the pond. This decreases the amount of organic matter in the pond. While this bacterium can remain dormant in colder temperatures, the pond water's constant supply of oxygen is enough to keep it alive until temperatures rise again in spring.
The Superfish pond heater floats on the pond surface and provides localized heat to maintain an ice-free hole in the pond surface. Place them in a saucer filled with water near a bright window to keep them healthy and happy during the winter. Tropical, non-hardy pond plants require a bit of work when it comes time to winterize your pond in the fall. Adorn your pond with shiny heart-shaped or kidney-shaped leaves against bright yellow flowers and a branching stem.
After the plant has completely died from frost, you can remove the excess dead parts of the plant and sink the plant container into the deepest part of the pond (deep enough to prevent the tubers from freezing). If your water garden isn't particularly prone to freezing during the winter, your lotus will be fine staying in the pond during the winter months. Before winterizing pond plants, it's a good idea to remove as much dead leaves and debris from the pond as possible and cut off wilted plants around the edge of the pond. Using a pond skimmer will help circulate surface water to prevent ice crystals from forming while cleaning up surface debris such as autumn leaves Cardinal flower, a perennial plant with vibrant cardinal red flowers, is an excellent pond plant for those who want add vibrant color and style to your backyard garden pond.
Hardy water lilies are one of the most popular pond plants and don't need much care during the winter. It's important to trim off any dead foliage and lower water lily containers into the deepest part of the pond (at least 2 to 3 feet deep and even more in colder climates) several weeks before the first frost.