Zantedeschia aethiopica (Calla lily) is a herbaceous perennial plant that is evergreen in regions with adequate rainfall and temperatures, and deciduous where there is a dry season. It is commonly known as Calla lilies, but is not a true lily, belonging instead to the arum (Jack-in-the-pulpit) family. These stemless plants have flowers and leaves that rise directly from rhizomes. They typically grow in clumps up to 24-36" tall, and feature large arrowhead-shaped leaves and extremely showy flowers consisting of a yellow finger-like spadix surrounded by a bright white spathe, borne atop a leafless stalk. The plant is commercially grown as a very popular cut flower.
The calla lily is winter-hardy in USDA Zone 8-10. The plant thrives in moist soils and full sun to part shade. In colder regions, containers may be overwintered outdoors in a sheltered location, sometimes with some protection, and brought back indoors before first frost. When grown year-round in containers, the plant must be brought indoors in winter before the first frost. Overwintering containers placed near a window with bright indirect light can make attractive houseplants.
For best performance, calla lilies require moist soil and bright light. Fertilization should be done regularly, monthly during the growing season. Propagation may be accomplished by division of rhizomes in early spring or by seed. The plant reseeds freely, often with variable results, and may self-seed and become weedy in some areas. It is important to exercise caution as all parts of the plant are poisonous and may cause skin irritation. Calla lilies may also be planted in mud at the edge of ponds or water gardens.