Calla lily flowers come in colors from white to purple to yellow. Not a true lily, calla lilies are native to Africa but can grow in United States Department of Agriculture Plant Hardiness Zones 8 through 10.
Calla lilies (Zantedeschia aethiopica) bloom in the late spring to early summer. They thrive when planted in the early spring. In some cases, they also bloom again in the autumn, according to the Floridata website.
Calla lilies may be planted in regions that are more temperate in the summer. Lift the bulb up in the fall, allow it to rest for a few months and then plant inside as a houseplant in the winter.
Calla lilies grow in full sunlight but do best with afternoon shade in more extreme climates. Since they are tropical plants, they grow best in moist soil. Calla lilies even grow in shallow water.