Calla lilies (Zantedeschia) are not a member of the lily family, but are actually a close relative of Jack-in-the-pulpit. Their blooms are treasured by gardeners and florists for their long-lasting beauty in cut-flower arrangements. As an outdoor plant, calla lilies are extremely tough, though they prefer high humidity. Grow calla lilies in sun to partial shade, or pot and grow them indoors. Keep soil moist and rich with organic material, and propagate them through division of their tuberous rhizomes. Only occasional maintenance pruning is required.
Snip off spent flowers at the base of the stem with scissors when they begin to fade. Calla lily blooms are quite long-lasting, so this will not happen frequently. Removing the spent stem will encourage the roots to send up more stems instead of concentrating on seed production.
Watch for insect pests. Some of the symtoms include curling or browning of the calla lily’s speckled foliage. Prune off affected leaves at the base of the plant. Dispose of trimmed leaves and do not leave them near the plant or dig them into the soil as mulch.
Prune calla lilies back in early summer, when flower production begins to tail off. Midsummer to early fall is a resting period for calla lilies. Cut back no more than one third of the foliage.
Root-prune or divide rhizomes in the fall when you dig them up before the first frost, much as you would with canna lilies. Slice rhizomes in two with a sharp knife. Cut out any soft or diseased spots on the rhizomes, and repot them in containers indoors for winter reblooming.
The most common calla lilies are white, but they are also available in hybrids of pink, orange and dark red.
All parts of calla lilies are poisonous, especially the rhizomes, which contain oxalic acid. Keep them out of reach of pets and small children.