Altar Lily Zantedeschia aethiopica

Calla lilies are a rhizomatous herbaceous perennial plant in the Araceae (Jack-in-the-pulpit) family native to Africa.  Contrary to the common name, they are not true lilies, the genus name is derived from Italian botanist Giovanni Zantedeschi (1773-1846) and the species name aethiopica means South African nodding to its origins.  This plant is known for its very large showy white flowers that are popular as cut flower in the floral industry.

They typically grow 2 to 3 feet tall and maintain their large deep green evergreen leaves in habitats with high rainfall and moderate temperatures but are deciduous when cold temperatures hit or there is a prolonged dry season.  They are commonly found growing along stream banks and ponds margins, marshes, where they can be considered weedy in some habitats.  

Plant in the full sun to partial shade in moist,  organically rich soil with plenty of leaf mold, rotted manure, and humus.  In hotter climates, partial shade is preferred to avoid leaf and flower scorch though flowering may suffer.  They are hardy to zone 8 but can survive in zone 7 if protected, otherwise, they may need to overwinter indoors. If you do not bring them indoors they can be considered an annual in the landscape.   If transplanting rhizomes dig a hole 4 inches deep and place them 12 to 18 inches apart when the weather has warmed up in the spring and the threat of frost has passed.  Typically found growing in clumps, they can be propagated easily by division in the early spring after the danger of frost has pasts or in the late summer or early fall after flowering.  To divide remove the entire clump from the ground and break it apart leaving some growing buds or "eyes" on each piece.  Let the pieces dry out and callus over the wounds for a day or two before replanting.  They can also be grown from seed planted sparsely to accommodate the future fleshy root growth.  

Callas will bloom from June to July with large showy funnel-shaped white spadix flowers.  They can survive in up to 12" of water so they work well along pond margins or rain garden. It is a popular choice for cutting gardens or mass plant it along a border.

Insects, Diseases, and Other Plant Problems:  Japanese beetles can feed on the leaves and flowers.  Rhizome rot is an occasional disease problem.

More information on Zantedeschia.