Our pre-rooted Hardy Water Lilies Rhizomes are extremely easy to grow to maturity in ponds or deck and patio containers. Important things to remember: Place the tubers at a 45° angle with the non-growing end against the side of the pot and the crown(where the leaves come out) towards the middle of the pot. Add fertilizer for water lilies. Lilies are heavy feeders and should be fertilized regularly. Press the soil around the roots, being careful not to cover the crown of the plant. They should be placed at a water depth of 6" to 12". When placing lilies in the pond, position them away from waterfalls and fountains as they prefer still water.