Water lilies thrive in full sun and most need at least 6 hours of sun a day in summer to be at their best and stand the best chance of flowering. Some varieties such as James Brydon, Chromatella, Perry’s Baby Red and Shady Lady will be fine in partial shade where they get only 4-6 hours sun a day. Any less than 3 hours sun a day and any lily will suffer and may even die. Ideally the water pH should be in the range 6.5 -8.0 and they do not tolerate salt water.
Lilies should never be placed by a fountain or any other water feature that will continually splash their leaves with water as they breathe through stomata on the upper surface of their leaves. Too much water on the surface of the leaves will effectively drown the plant at worst and even if not enough to do this water will flow into the open stomata and cause disease, which over a period of time can prove fatal. They also don’t react well to moving water, so should be placed where there is little water movement: in large ponds and lakes exposed to wind which causes a lot of water movement and waves lilies can wither and die.
Water lilies are best planted in aquatic baskets, not solid pots, suitable for their stage of development and cultivar. They can also be planted directly into the bed of a natural pond, although they will be much harder to lift and divide when they need to be thinned out.
Ensure that the Water lilies are planted at the correct depth for the cultivar. Check depth guides for the individual Water lilies on this web site or see Planting depths for Water lilies for a general guide. As a general rule it is better to plant shallower than too deep.