Calla lilies are also known as Zantedeschia or arum lilies. According to the Calla Lily Guide, “the calla lily is not a lily at all, and although it is related to the calla genus, it is not really a calla either.” Depending upon the variety, the arrow-like leaves of this plant can grow upwards to 39 inches tall, with trumpet-like blossoms in colors including white, cream, pink, red, apricot, yellow, orange and purple. These perennials are easy to grow and will provide a beautiful addition to your garden for many years.
Select a site for your calla lilies. They grow well in full sunlight, but in areas with extreme summer heat, the plant does better in light shade. Select a spot that is sheltered from strong winds. They need moist, rich soil that drains well.
Prepare the soil several weeks in advance. Dig up the soil and remove weeds and garden debris. Amend the soil by mixing in compost or well-rotted manure.
Plant the calla lily rhizomes in April. Rhizomes look like a fleshy, tuberous root with small roots coming out of one side; plant this side downward. Plant the rhizome 4 to 6 inches deep and space them 12 to 18 inches apart. Water thoroughly to settle the soil around the rhizome. Use plant markers to indicate the location of the rhizomes.
Water the calla lily regularly, but do not over water; it needs moist, but not soggy, soil. Keep the soil moist when the plant is actively growing; a layer of mulch will help the plant retain soil moisture.
Watch for shoots to appear in early summer. Soon, the long slender leaves will form a thickness at the end; these are the flower buds. Apply a liquid fertilizer when the buds appear and reapply every two to three weeks while the plants are in bloom.
Watch for leaf spots that cause dark blotches on the plant. Cool, damp conditions cause this and can result in premature leaf drop. Destroy any affected parts (do not compost) and treat the remaining calla lilies with fungicide.
Remove flower stems as they fade. Add a layer of dry leaves to prepare the calla lilies for winter. In the spring, dig up the rhizomes and divide them. Make sure there are roots on each section of the rhizome before you replant them.