Fall is a bittersweet season for pond enthusiasts. The crisp, clear water of the autumn pond spectacularly reflects the riotous color of leaves on the trees above, providing great enjoyment. At the same time, it's sad to say goodbye to your beautiful water lilies bobbing on the pond's surface.
As fall approaches, hardy water lilies stop producing leaves that grow to the surface of the pond and start producing leaves that grow only a few inches high. To over-winter hardy water lilies, trim off the mature leaves a few inches above the crown and drop the pot to the lowest depth of the pond.
If your water lilies are permanently planted in pockets at the lowest part of your pond, all you need to do is remove the dead foliage. Hardy water lilies need to have a period of dormancy which is onset by cold water, so do not bring them into a heated indoor pond to keep them growing.
Tropical water lilies will flower up to and past the first light frost as they have no idea what winter is and no need to prepare for it. Tropical water lilies can be over-wintered indoors in water over 50 degrees F, or they can be taken out of the pot and stored in moist sand. The warm water method isn’t practical for most, and success with the moist sand method is variable, usually ending in the loss of the tuber to mold or rot. Botanical gardens with trained horticulturists expect to lose many of the tropical water lilies they store every winter. Start over each year as you do with your terrestrial annuals.