Gardeners should procure bulbs that are guaranteed to bloom in lavender, if they want lavender calla lilies. Purchase bulbs from a retailer or divide an established calla lily plant to get bulbs for planting.
Plant calla lilies in the fall in warm regions above USDA growing zone 6, or in early spring in colder areas. This gives the bulbs time to take root and grow for their spring and summer blooms.
Calla lilies require quick drainage and full sun all day if they're to grow and bloom. Gardeners should never plant calla lilies in areas that gather water or sit in the shade.
Calla lilies are perennials, and return year after year from the same set of bulbs. Many gardeners dig their bulbs up after the bloom, to store them for the remainder of the summer. Gardeners in cold areas like Illinois should dig their bulbs up and store them in winter to protect them from cold.