Q: I am working to shut down my water garden for Winter, but I’m unsure of what to do with the aquatic plants? Do I pull them out? If I leave them will they come back next year? – Bill of Wisconsin
Aquatic Plant Maintenance: Every type of aquatic plant needs to be taken care of in a different way. The biggest factor to remember is to make sure that the roots of the aquatic plants do not come into contact with the ice. Anything “hardy” will usually come back each year as long as the roots do not come in contact with ice. Anything “tropic” or “non-hardy” will parish during the Winter times. The following are the steps to take for each type of aquatic plant.
Hardy Water Lilies, Marginals & Submerged Aquatic Plants: Simply trim to around 3 inches above the root system. Water lilies & submerged aquatic plants should already be planted 18″ to 24″ deep making it very unlikely for them to be frozen.
Tropical & Floating Aquatic Plants: Any tropical water lilies, tropical lotsus, or tropical marginals should be treated as annuals. They will not survive the harsh Winter conditions. If you would like to try and keep them, you can place them in pots and bring them indoors, but this can be difficult to keep them alive. As for floating aquatic plants such as: Water hyacinth, lettuce, etc., treat these as annuals as well. Most floating plants are realtively inexpensive to replace each year.
Hardy Lotuses: Trim back the foliage after it has died and turned brown. If leaves are cut while still green, the plant is susceptible to diseases entering through the hollow stems. If stem must be cut while still green, make sure to trim above the waterline, so water does not enter the stem and essentially drown the plant. In colder climates, lotus tubers must not be allowed to freeze in the winter, and containers should be moved to a cool but frost-free area, such as the bottom of a pond that is deep enough to keep the tubers from freezing.