Calla lilies, or zantedeschia (zan-teh-DES-kee-ah), are a wonderful flower for both the garden and as cut flowers to bring indoors for arrangements. Champagne flute shaped blooms in wide range of colors, plus leafy green foliage make this a favorite summer bloom in my garden.
Plant callas after the last frost date in your area. It usually takes about 60 to 90 days for the tubers to bloom, so if you live in an area where summers are short, try starting them indoors a few weeks before planting time. If you are planning on planting them in the ground, wait until the soil warms up a bit. I plant mine around the same time that I put out my tomatoes. If you live in a mild climate choose an area that receives full sun, but those who experience hot summers should plant their calla lilies where they will receive partial shade. Plant the tubers 2 to 3 inches deep and about 8 to 10 inches apart in soil that is consistently moist, but well drained. Add 2 to 3 inches of mulch to help keep moisture in and the soil temperature down. To produce lots of blooms, feed your calla lilies once a month with an all-purpose fertilizer.
Calla lilies are only cold hardy to zone 8. That being said, gardeners in cooler climates can still grow them. You just have to dig them up in the fall before the first frost and store them for winter. To make that job easier, plant your callas in a container and bury them container and all in the garden. Then in the fall just pull out the container and store them in a cool, dry place for the winter. Calla lilies actually perform better when they are slightly root-bound, so they are well suited for container life.