How to Grow Black Calla Lilies

Prepare to plant calla lilies in fall, around the first frost, in U.S. Department of Agriculture growing zones 8 to 11. This gives the bulbs the winter to grow and establish. Callas bloom from spring to summer, but do best with this cold resting period. In USDA zones 7 and lower, where the winters are more dramatic, plant callas in early spring, before the last frost. This protects them from winter but gives them their cold stratification.

Find planting sites where the black callas will get full sun and good drainage. Callas will grow in partial shade, but will not bloom well, and will rot when left in water or wet, thick soil. Make sure that any site has at least 1 foot of space per bulb.

Dig into the top 10 inches of soil in sites set 1 foot from each other, and mix 5 inches of quick-draining garden soil in. Callas need loose, airy soil to allow for growth and root development, and won't grow in compacted natural soil. The bulbs hold all the initial nutrition they need, so you don't have to add organic compost or fertilizer at this time.

Set bulbs 4 to 6 inches deep in the hole, with noses pointed up, and refill with the soil mix. Water the bulbs with 8 inches of water to wet the entire bulb. Leave the bulbs until they bloom, with minimal watering of only 1 inch a week.