The calla or arum lily is an old-fashioned plant of which I am very fond. They grew lushly in the garden of my childhood, sited as they were nearby the septic tank! I was intrigued by their dramatic, furled blooms, which seemed to have funeral overtones, though these days they have become very trendy again in floral arrangements.
They grow from a rhizome and come from South Africa, and are regarded as reasonably frost hardy. Zantedeschia belong to the Araceae family of plants, which includes Alocasia, Colocasia, Spathiphyllum and Philodendron, most of which do well in our climate. The basic form grows 60-90cm in height and flowers from late winter till around the end of spring. Leaves are lush and arrow-shaped. It has a large, dead-white funnel-shaped spathe, with a prominent central spadix. The texture of the spathe is very dense. There is a lovely cultivar called 'Green Goddess', which has flowers suffused with green, and there are various dwarf cultivars, such as 'Little Gem' and 'White Gnome'. I sometimes find these tend to end up growing as tall as the normal ones, for some reason!
The plant likes shade, with some moisture. Indeed, they can be grown in a pond. I like to team them with a flower of airy form, such as the renga renga lily (Arthropodium cirratum) as a contrast. The calla lily will self-seed, so be vigilant in deadheading them as soon as the flowers fade. There are Zantedeschia species with yellow or mauve to purple blooms, and hybrids of these, known as New Zealand Mixed Hybrids, with flowers in beautiful colours of pinks, red, bronze and orange; some have speckled foliage. I have never had much luck with any of these ones. They seem to need warmth and very rich soil, and are certainly not as easy to grow as Zantedeschia aethiopica!