Arum Lilies

Arum Lilies Overview

Zantedeschia is a genus containing around 8 species of herbaceous, perennial flowering plants, native to southern and East Africa. This genus is popular for its striking, upright spathes that form around a solitary, finger-like spadix. Flower colours include white, yellow, orange, pink, red and purple. Zantedeschia plants are deciduous; they grow up to 1m high and survive the dry season through water storage in their rhizomes or tuber - in the wild, these are buried in crevices of rocks. This is an adaptation to keep the tubers and roots cool over the dry season, and in the rainy season, the plants benefit from water channelled into the crevices. Plants in the genus prefer full sun or partial shade, soil rich in humus, and seasonal watering. Zantedeschia aethiopica grows in both the summer and winter rainfall areas and is evergreen, but will become dormant in dry conditions. All other species (except Zantedeschia odorata ) occur in the summer rainfall region and are dormant in winter. They must, therefore, be kept dry in winter. Zantedeschia odorata, being a winter rainfall plant, is dormant in summer and must be kept dry in the summer months. Tender forms (including Calla Lilies) should be fed fortnightly with a high-nitrogen fertiliser when in active growth, but withhold feed during flowering. A high-potassium feed (e.g. tomato fertiliser) can be given once a week after flowering. Indigenous to South Africa, today, numerous Zantedeschia cultivars are available as garden and pot plants and, due to their decorative and long-lasting spathes, they are popular as cut flowers. These cultivars generate high revenue in New Zealand, the USA and the Netherlands. A number of hybrids have been developed that fall in two main groups: Elliottiana hybrids, which usually have dotted leaves and yellow spathes and golden yellow spadices, and Rehmannii hybrids, which have unspotted leaves and white-pink or dark purple spathes surrounding yellow spadices. Depending on the species, members of this genus can be grown in containers or flower borders/beds in a variety of garden styles, with the species Zantedeschia aethiopica often being cultivated as a marginal aquatic plant. The centre of diversity for the genus is Lydenburg in Mpumalanga where four species occur. Plants of Zantedeschia grow in the grassland, savanna and fynbos biomes, in full sun, less often in partial shade, and they occur in areas with seasonal rainfall. All species occur in the summer rainfall areas, except for Z. odorata at Nieuwoudtville (winter rainfall), and Z. aethiopica which is widespread and commonly found in marshy areas.