It’s difficult to focus on sensible information on the subject of Zantedeschia because they are so exquisitely lovely. It seems horribly insensitive to mention ‘compost’ or, worse still, ‘manure’ on the same page. I’d rather wax lyrical about brides and slim beauties. Calling an arum lily by its Afrikaans name, ‘wit varkoor’, seems almost indecent (they are so named because the shape of the leaves is just like a pig’s ear, and also because porcupines and wild pigs dig up the fat rhizomes and eat them)!
However, you can fortify yourself by browsing “Zantedeschia / Images” online before we go into details and if you can tear yourself away from the unforgettable images, you can return to some of the ins and outs associated with these gorgeous South African bulbs.
Zantedeschia are very versatile plants and are justly popular in gardens all over the world. Most commonly known is Z. aethiopica (nothing to do with Ethiopia – way-way-back-in time the name was used to refer to anything from the dangerous, unexplored southern parts of the African continent). Z. aethiopica are the hardiest members of the family and thrive in such a wide range of conditions that you will find them in huge clumps in the open beds of streams in and around Cape Town, along salty, humid coastal paths and in mountainous grasslands where the winters are freezing and the air thin. The common denominator is water - they love marshy conditions. You can even pop them in a pot and submerge it in your garden pond but Z. aethiopica will be just as happy in a well-composted garden bed in the sunshine or even the shade, although white arums do flower better in full sun.
Quite apart from the common arum (if anything so good looking can be called ‘common’), there are four other popular members of the family as well as a host of irresistible cultivars, mainly hybrids of Z. rehmannii, Z. albomaculata and Z. jucunda. Unlike the rhizomes of Z. aethiopica, these are tubers. These are often referred to as calla lilies and they come in a range of rich and vivid colours that have earned them dramatic names like ‘Black Panther’, ‘Inferno’, ‘Ruby Tuesday’ and ‘Fire Dancer’.
I find it fascinating to note that what we think of as the ‘flower’ is technically known as a ‘spathe’ to botanists and other real fundis. If you want a real treat, look through a magnifying glass at the central ‘tongue’ of the flower. It’s called the spadix and is an intricate arrangement of tiny, tiny real flowers arranged in a perfect spiral What is really intriguing is the fact that the top 7cm is where the male flowers ‘hang out’ while the female parts of the flower are clustered modestly below. The miniature flowers are visited by bees and insects, attracted by a gentle scent and by glowing colours, and cross pollination takes place because the pollen laden anthers ripen before the ovaries below. Isn’t nature magnificent?
Like arums, calla lilies should be planted in late winter or early spring, about 5cm under the surface of rich, well-composted soil. As usual, feeding as directed with a good fertilizer will add to the strength of the plant and the beauty of its flowers. In addition, as Zantedeschia are best left undisturbed for several years, it’s a good idea to top dress them with a layer of well-rotted manure in the summer. Callas do not tolerate over-watering. Only Z. aethiopica can stand marshy conditions. All other Zantedeschia must be given very well- draining soil and watered only when required. This is usually every 4th day in the garden and every 3rd day in a pot.
I cannot imagine my garden without its lush, leafy Zantedeschia. I have clumps of Z. aethiopica in the shade around my bird bath and coloured callas in the sun in pots outside my lounge windows where they are in flower right now. I also have arums in a riot in a damp spot where a natural spring rises. They have low-growing, purple-leaved plectranthus at their feet and Cyperus prolifer (dwarf papyrus) at their elbows – another plant that likes mushy, wet soil. When they are not in flower, their leaves are huge and abundant – fabulous as a contrast to the feather duster papyrus and dark green of the velvety plectranthus.