Calla lilies produce pink, red, purple, white and yellow flowers. They thrive in United States Department of Agriculture Plant Hardiness Zones 9 to 11, but grow in containers in areas as cold as Zone 2. They bloom as the weather becomes warmer after winter.
Calla lilies will bloom from late spring to early summer if planted in the spring. Leave the bulbs outside after they flower and they come back the next year.
Plant the calla lily rhizomes in the spring about 1-inch deep in the soil, leaving a space of 1 to 2 feet between plants. To get a head start, you can also start calla lilies in containers indoors during the winter.
To save the calla lily rhizome after the season, wait for the leaves to wither in the fall. Dig the rhizome, let it dry and then store it at 10.0 to 15.5 degrees C to replant next spring. (ref 2)