Native to South Africa. Basal clumps of long-stalked, shiny, rich green, arrow- or lance-shaped leaves, sometimes spotted white. Flower bract (spathe) surrounds central spike (spadix) that is tightly covered with tiny true flowers. Deer usually leave callas alone.
Z. aethiopica. COMMON CALLA. To 24 ft. tall. Forms a large clump of unspotted deep green leaves that are 112 ft. long, 10 in. wide. Pure white or creamy white, 8-in.-long spathes on 3-ft. stems appear mostly in spring and early summer. 'Green Goddess' is a robust selection with large spathes that are white at the base, green toward the tip. 'Hercules' is larger than species, with big spathes that open flat and curve backward; leaves are spotted with white. 'White Giant' is aptly named, with flowers that may reach 67 ft. tall; leaves are thick, leathery, and spotted with white. Dwarf 'Childsiana' grows just 1 ft. tall. 'Pink Mist' grows 12 ft. tall, with palest pink flowers with a darker pink eye.
Z. albomaculata. SPOTTED CALLA. Grows to 2 ft. high, with bright green, white-spotted leaves 1112 ft. long, 10 in. wide. Creamy yellow or white, 4- to 5-in.-long spathes have a purplish crimson blotch at base. Blooms from early spring into summer.
Z. hybrids. Plants are usually about the size of Z. albomaculata and bloom in late spring and summer. Leaves are typically spotted, though some selections have solid green leaves. Spathe colors include cream, buff, orange, pink shades, lavender, purple. Captain Murano' has hot pink spathes with an orange base. Spathes of 'Edge of Night' are darkest purple. 'Picasso' blends yellow and purple.
Z. rehmanii. RED or PINK CALLA. To 1122 ft., with narrow, lance-shaped, unspotted green leaves to 1 ft. long, 212 in. wide. Pink or rosy pink spathes to 5 in. long in midspring. 'Alba' has white spathes. 'Superba' has dark pink spathes.
Common calla (Z. aethiopica) is basically evergreen but goes partly dormant even in the Tropical South. It will thrive in almost any moist, even boggy soil all year. It cannot withstand storage and so should be grown as a container plant where winter temperatures fall below 10F.
The other callas described here die to the ground yearly in fall and reappear in spring. They need slightly acid soil and regular water during growth and bloom, followed by a resting period in which, ideally, water is withheld. In rainy climates, rhizomes will tolerate moisture if soil is well drained. Store potted rhizomes dry in their containers. Beyond their hardiness range, rhizomes of deciduous species can be dug and stored over winter, then replanted in spring.
Where callas are hardy, plant all types in fall, setting rhizomes of Z. aethiopica 46 in. deep, those of other species 2 in. deep. Space rhizomes 812 in. apart. Leave undisturbed until overcrowding causes a decline in vigor and bloom quality. Elsewhere, plant rhizomes in spring and lift them in fall.