Winter Care of Water Lilies

Shimmering waterlily leaf frozen in dark pond
Rosmarie Wirz / Getty Images

There are two main types of water lilies: hardy and tropical. Both will require some TLC to make it through the winter in cold climates. That’s why a lot of gardeners grow water lilies as annuals, composting them at the end of the season.

But if you have space and the wherewithal, it is possible to overwinter both hardy and tropical water lilies. You should expect to have varying degrees of success since there are many things that can go wrong when trying to overwinter water lilies. Outdoors, the weather can surprise you by becoming colder than expected or with wide temperature swings. You can control conditions better indoors, but sometimes the plants simply aren’t able to adjust.

If you’d like to try overwintering your water lilies, here are some suggested methods for winter care of water lilies.

Winter Care of Tropical Water Lilies

Tropical water lilies are the most difficult to overwinter. Although tropical water lilies do go dormant in winter, they are only hardy to about USDA Hardiness Zone 9. They will freeze and die if left in a cold pond over winter. It’s very common to grow tropical water lilies as annuals. If you want to try overwintering your tropical water lilies, here are some ideas to help you succeed:

  • Store your tropical water lily in a greenhouse, a heated aquarium, or in a heated room under grow lights. Lift the pots in late September/October. You can move your water lilies to smaller pots for the winter if you like. Lift the plant and trim back some of the leaves and roots. Replant in a 1-gallon container. Then place the pot in a small tub of water and keep it at about 68 degrees Fahrenheit. The idea is to keep the water lily alive, but not actively growing, so don’t fertilize or worry about providing too much space.
  • You could also store the plant outside of the pot if you keep it damp. Lift the entire plant, cut off most of the top and store the rhizome in a plastic bag with some damp peat moss or sand. Store the bag somewhere dark at about 50 to 60 degrees F. Check periodically to make sure it’s not getting dry or soft and moldy.
  • If your plant has tiny tubers growing at the base, you can remove these offsets and store them in water or damp peat moss, again at about 50 to 60 degrees Fahrenheit. They should start to sprout in the spring and can then be potted up.

Wait until the water warms in your pond next spring, before bringing your water lily back outdoors. The water temperature should be about 70 degrees, for tropical water lilies. If it’s too cool, the plant will revert back to dormancy or be killed off by frost and you don’t want to do that after all your efforts over the winter.

Winter Care of Hardy Water Lilies

Hardy water lilies are truly hardy to about USDA Zone 4, but potted water lilies will still need some protection. You don’t want them sitting in your water garden if it freezes solid or even if it tends to freeze and thaw repeatedly. Here are some ways to keep your hardy water lily alive through the winter.

  • Move the water lily: Hardy water lilies will go dormant for the winter. The foliage will die back or become sparse. When this happens, move the water lily, pot and all, to the deepest part of your pond, where the water doesn’t freeze solid. Hardy water lilies actually enjoy a cold, dormant period. Leave it there for the winter and fish it back up as the water warms in the spring. It should resume growing sometimes around April.
    If you don’t have a deep enough pond to keep the water lily below the freezing level, you can try one of these other methods to protect it.
    Take the water lily out of the pot and bury it completely in the ground. Mark the spot, mulch it well, then dig and repot the plant in the spring. (We’ve never tried this and suspect a lot depends on the type of winter you have. A good snow cover should keep it fine, but a dry, cold winter could kill it.)
  • Insulate the pond: If it’s a small pond, you could insulate the whole pond by covering it with boards and then a layer of straw or old blankets or rugs. Be sure to remove all the coverings as early in the spring as possible or it will heat the water and cause premature sprouting. (This sounds like a lot of work, but think of all the work you save by not having to scoop leaves and debris out of the pond in the spring.
  • Store it inside: Bring the water lily indoors for the winter and store in a cool basement or heated garage, about 50 degrees Fahrenheit. Either bring in the whole pot and place it in a plastic bag or box. Check it periodically to make sure the soil remains moist. Or remove the plant from the pot and store the tuber in moist peat moss or leaves. (Don’t expect your potted water lily to make a good houseplant. It still needs to go somewhat dormant and won’t be particularly attractive.)

Water lilies take some experience to successfully overwinter year after year. Since they can be expensive plants, it’s worth trying. Remember to check on them every few weeks during the winter. Just like with any other bulb stored indoors, it doesn’t take long for them to dry out or rot if conditions aren’t ideal. And most importantly, remember to get them potted up and back outdoors gradually in the spring, so you can enjoy their hard-earned blooms again.