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Fall and Winter Care of Water Gardens

Many gardeners are enjoying a renewed interest in water gardens. A water garden adds such a special dimension to your yard and fish make great pets. A water garden that is set up properly will take care of itself naturally all through the growing season. Submerged plants and scavengers will keep algae growth from getting out of control. However, water gardens do require late season attention for their survival. 

Care of Water Garden Fish

Keep falling leaves and twigs out of the water garden to prevent injury to the fish. Prevention is also easier than having to clean the entire water garden in the fall. Netting stretched across the water garden is an easy preventative to catch leaves or use a skimmer to remove leaves on a regular basis. 

If your water garden contains fish, be sure to feed them extra food beginning when temperatures cool and continue until the water temperature drops below 45°F. This allows the fish to build up additional fat stores for winter. If the fish are to remain in the water garden throughout the winter, it is necessary to keep an area free of ice throughout the winter. This allows the exchange of gases such as carbon dioxide, methane, and hydrogen sulfide that are produced from decaying organic matter. The build up of these gases is toxic to fish. A one-foot diameter opening per 100 square foot of water garden surface area is adequate. 

Care of Water Garden Plants

Stop fertilizing water garden plants when the daytime water temperature drops below 60°F. This will give the plants an opportunity to go dormant. As the leaves of hardy plants yellow or are frozen, cut the leaves off back to the crown. The short, small leaves produced late in the season should remain attached. 

Lower hardy plants to the bottom of the water garden where they will survive the winter. If there is danger of the water garden freezing solid, remove the plants in their containers from the water garden and place them in a non-freezing area. Put the containers inside a plastic bag and cover with moist material such as newspapers or peat moss to retain moisture. 

Tropical water lilies and other non-hardy water plants can be over-wintered in various ways. The goal is to keep the plants alive, but not growing vigorously. Plants can be kept in a washtub, tank or even in an aquarium in a greenhouse or under grow lights. The water temperature should be kept at around 70°F.

Plants that form tubers such as tropical water lilies can also be stored as a dormant tuber. The plants should not be fertilized after August. This forces the lily to form a tuber. Allow the plant to remain in the water garden until all leaves are killed by frost. A hard tuber must be present in order for the plant to survive. Once tuber formation is complete, remove it from the container and wash it off. If the tuber has roots or stem tissue attached, let it air dry for a few days and then break the roots and stems off. Place the tuber in a jar filled with distilled water and store it in a cool (55°F), dark location. Check the container regularly and replace the water if it is discolored.

In the spring, place the container in a sunny warm location. When sprouts form, plant the tuber in sand. Place the planted tuber in a container of water so that developing leaves can float. When the leaves have grown to the water's surface and white feeder roots can be seen, remove the plant from the tuber and plant it into a standard container. Place the lily in the outdoor water garden when the minimum water temperature is 70°F or more. 

Water Garden Cleaning

If the water garden has an inch or more accumulation of silt, leaves or debris, the water garden requires cleaning. Place some of the original water garden water into a holding tank for the fish. Cover it so your fish won't jump out. Remove the remaining water from the water garden. Remove and cover plants with wet newspaper or other moist material and place the plants in a shady location. After all the water is removed, scrub the water garden floor with a stiff brush and water. Leave the algae growing on the side of water garden. Rinse the water garden and drain once again. Fill the water garden with fresh water and allow any chlorine to evaporate and the water temperature to stabilize. Blend the new water garden water with water in the holding tank until its water temperature is within 3°F. of the water garden water.

Release your fish and scavengers into the water garden. Divide and repot those plants that need it and put them back in the water garden or store them in a frost-free area for winter.
Water gardens are a beautiful addition to the home landscape. However, they are not a low maintenance addition. For a lower maintenance water garden, select only hardy species and install a water garden that is deep enough for overwintering plant material. Installing a pond heater is also an excellent choice.

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