Dividing Casablanca lily every three to five years or whenever growth begins to slow will keep the lily vigorous and healthy. Clumps of Casablanca lilies can be divided in autumn.
A spade or garden fork is used to dig the entire clump of Casablanca lilies. The plant is dug carefully to avoid cutting into the bulbs.The plant is then lifted from the soil and the bulbs are separated by hand or with a sharp knife.
Casablanca lily bulbs are planted in fertile, well-drained soil and full sunlight. Soil is usually amended with rotted manure or compost. The lily bulbs are planted 6 to 10 inches deep.