About

Zantedeschia () is a genus of eight species of herbaceous, perennial, flowering plants in the aroid family, Araceae, native to southern Africa (from South Africa northeast to Malawi). The genus has been introduced, in some form, on every continent other than Antarctica.

Common names include arum lily for Z. aethiopica, calla and calla lily for Z. elliottiana and Z. rehmannii. However, members of this genus are not true lilies (which belong to the family Liliaceae), and the genera Arum and Calla, although related, are distinct from Zantedeschia, despite visual similarities. The colourful flowers and leaves, of both species and cultivars, are greatly valued and commonly grown as ornamental and garden plants.

How to grow it

All Zantedeschia produce large, showy flowers spathes and are often grown both as ornamental plants and for cut flowers. Zantedeschia are relatively hardy plants, but some are more winter-hardy than others. In this regard there may be considered two groups, a hardy outdoor group with large white flowers (arum lilies) and less hardy group with white-spotted leaves and flowers in many colours (calla lilies), such as yellow, orange, pink and purple.

Safety

Zantedeschia shares the general properties of the family Araceae in causing contact irritation. Zantedeschia species are also poisonous due to the presence of calcium oxalate crystals in the form of raphides. All parts of the plant are poisonous, typically producing local irritation or a burning sensation in the mouth and occasionally vomiting and diarrhea. However leaves are sometimes cooked and eaten.

Where it grows

All species are endemic to central and southern Africa, from Nigeria to Tanzania and South Africa. Z. aethiopica grows naturally in marshy areas and is only deciduous when water becomes scarce. It grows continuously when watered and fed regularly and can survive periods of minor frosts. Z. aethiopica is a very strong and sturdy plant, being able to grow in many soils and habitats, multiplying by rhizome-offsets; it is naturalised and regarded as a weed throughout much of the world. Z. odorata is a rare species, resembling Z. aethiopica, but deciduous and smelling like freesia, endemic to a few localities in South Africa. Z. albomaculata is a widespread and variable species, growing from South Africa north to Kenya, varying in shades of white to cream and pink to orange-shades. Z. jucunda and Z. pentlandii are rare species with large yellow showy flowers. Z. rehmannii is a pink-flowered species with sword shaped leaves. Z. elliotiana is known from horticultural sources only and is probably of hybrid origin.

Uses

Extensive commercial production of Zantedeschia for cut flowers and/or planting material occurs in California, Colombia, New Zealand and Kenya. Plant breeders in California and New Zealand continue to produce an extensive range of new hybrid cultivars. The so-called white calla derived from Z. aethiopica. All varieties with flowers with shades of yellow, orange, red, purple are mainly derived from Z. albomaculata, Z. pentlandii, Z. elliottiana and Z. rehmanni.

Other Zantedeschia plants

Calla lily · Golden Arum Lily · Pink Arum