Hardy water lilies can be grown from zones 3 to 11 in the US, which covers most of the contiguous states. They are available in various colors ranging from whites and creamy whites to many shades of yellows and pinks. You can plant hardy water lilies in containers in your garden pond, or directly in the ground. Either method allows you to overwinter your hardy water lilies and treat them like perennials.
Grow Hardy Water Lilies in Containers
Plant hardy water lilies in containers for small water gardens or for use in ponds with shelves or ledges. Use at least a 3 gallon container; a larger container produces more and larger flowers. Fill the container with heavy clay garden soil or clay river bottom soil. Plant the rhizome along the side of the container at a 45 degree angle, just deep enough to barely cover the growing point of the rhizome. Face the rhizome so that the growing point faces the center of the container.
Cover the soil in the container with a layer of pea gravel. This will deter fish in your pond from rooting out the rhizome. It also helps keep the soil in the container when you move the plant.
Lower the container into your pond. The lily will grow faster if you leave the container only a few inches below the surface of the water until it begins to sprout. Then lower it to the recommended depth, usually 15 to 18 inches for full-sized lily plants.
Trim dormant foliage in the fall, and lower the containers for the winter. Lift them up again in the spring. Overwinter lilies in the containers only if your water garden is at least 18 inches deep and does not freeze solid. If your pond is shallow, lift the containers and store the dormant rhizomes in a cool, moist place for the winter.
Grow Hardy Water Lilies in Pond Soil
Plant hardy water lily rhizomes directly in the earthen bottom in a shallow area of your natural pond. Use a long handled shovel underwater to open a hole just large enough for the rhizome. Place the rhizome into the hole with the growing crown side up, and barely cover it with the soil.
Leave the rhizomes in the pond all winter if it is at least 18 inches deep. As long as the rhizome does not freeze solid, the lily will grow back in the spring.
Hardy water lilies in natural ponds will propagate by themselves and spread in shallow areas. They usually do not require any special care once they are established.