As fall comes into full swing, the days become shorter, with less hours of sunlight. The temperatures slowly start to drop, chilly breezes giving a taste of winter. The first official day of fall is September 22nd, but summer weather can linger, keeping the days warm until November or even early December. During the year, you’ve worked hard to keep your pond plants healthy and vibrant. Plants need to be prepared for the cooler fall weather, particularly for the first frost, so they can stay strong until spring.
Plants range in “hardiness,” or how resilient they are to harsh weather conditions. You can check the plant hardiness zone map to see which zone you live in, and which plants are suited for your winters. Hardy pond plants need a little TLC, and they are ready to ride out the cold weather in the pond. Less hardy plants that are better suited for warmer weather (typically tropical varieties) need to be relocated indoors or replanted in the spring. It can be expensive to repurchase new plants each spring. You can prepare your pond plants so they will last through the first fall frost and throughout winter.
During fall the goal is to keep the water as clean as possible, minimizing the amount of debris in the water. Leaves are a major battle. Organic material like leaves and lawn clippings that make their way into your pond during fall, start breaking down and releases harmful gases during the wintertime. As the surface freezes, it’s harder for gases to escape and oxygen levels can drop. Scooping out any leaves, grass, trimming back plants, and not overfeeding fish, will help keep the water healthy throughout winter. Fish need less food as the temperatures drop, this guide for feeding your fish in fall and winter will help you prevent overfeeding.
Here are some tips for preparing your plants for fall:
Water Hyacinth, Water Lettuce, and Frogbit
Floating plants are not very hardy. They should be removed from the pond before the first freeze. You can use them for compost to help fertilize other plants, or you can try to keep them indoors until spring. Floating plants require warm water (70°F or warmer) and lots of sunlight.
Soft Stem Rush, Brooklime, and Variegated Water Celery
These marginals can handle cold weather and freezing temperatures. You can leave them in your pond throughout fall and winter. Once the leaves begin to turn yellow and brown (typically after the first freeze), you should stop fertilizing. The fertilizer can turn into excess nutrients in the pond. Trim the dying parts of the plant away, leaving around 2 inches of plant above the surface.
Papyrus, Canna, and Bluebell
Tropical plants enjoy sunlight and warm weather; they will not survive the winter. You can treat them as a garden annual, and replace them each season. If you want to try to keep them until spring, you can put them in a pot with no holes and move them indoors before the first freeze. You want to use heavy garden soil and place them in a warm place that receives the most amount of sunlight and humidity. Once spring arrives, and the sunlight warms the pond back up, you can transfer the tropical marginals back into the water and fertilize as normal.
“Hardy” Water Lilies
If your pond doesn’t freeze all of the way through, these water lilies can be kept in the pond throughout winter. Once the water lilies’ flowers turn yellow and become less frequent, you should trim the existing leaves 2 to 4 inches above the crown. You can then place the pot in the deepest part of the pond.
“Tropical” Water Lilies
These lilies can keep flowering up until the first frost, afterwards they should be moved inside or composted. If moved inside, they should be kept in water that is warmer than 50°F. It is hard to keep tropical lilies healthy until spring, they are susceptible to tuber rot and mold. It may be easier to treat them as annuals and add brand new lilies to your pond in the spring.
Lotus plants need to be carefully trimmed. The leaves should be trimmed back once they are brown and beginning to die, if they are trimmed while still green, the plant’s tuber can become infected with disease. Lotus will not survive in the shallow parts of the pond that will freeze through, they need to be moved to the deepest part of the pond, below the freezing water. After the winter, they should (hopefully) emerge as healthy happy plants!
Fall can be a bittersweet season, the changing leaves and cool breezes remind us that summer has ended, and winter is coming. In most places, outdoor water gardening pauses in winter and doesn’t resume until spring. Your pond may be shut down for a few months, your fish sluggish, and your plants bare. You may feel a little glum, but there are plenty of fun indoor projects to keep your busy until spring, when you can tackle your gardening wish-list! Preparing your plants for the fall will get them ready for winter, so they can blossom in the spring. The extra care will help keep your pond water healthy, and save you money. Your plants will greet you in the spring, and you can start water gardening again!