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This is an old fashioned, but very rewarding garden plant. Zantedeschia
is named after Professor Zantedeschi, probably Giovanni Zantedeschi,
1773-1846, an Italian physician and botanist, although there is
some uncertainty about this. The name aethiopica is not directly
related to Ethiopia. In classical times it meant south of the known
world i.e. south of Egypt and Libya. Several southern African plants
were given this specific epiphet early on. It is an excellent cutflower and lasts a long time in water. Nowadays there are other forms of this species which will enliven an old theme. The 'Marshmallow' with a creamy pink spathe (outer "petal" which is actually a modified leaf) and rose-pink throat and the 'Green Goddess'with a green and white spathe. There is also an attractive form with leaves spotted white. This lovely plant was introduced to Europe very early on, apparently before Van Riebeeck had established the refreshment station at the Cape. It is also illustrated in an account of the Royal Garden in Paris in 1664. It was sent as one of the interesting plants of the Cape to Europe by Simon van der Stel some time before 1697. The striking arum lily "flower" is actually many tiny flowers arranged in a complex spiral pattern on the central column (spadix). The tiny flowers are arranged in male and female zones on the spadix. The top 7 cm are male flowers and the lower 1.8 cm are female. If you look through a hand-lens you may see the stringy pollen emerging from the male flowers which consist largely of anthers. The female flowers have an ovary with a short stalk above it, which is the style (where the pollen is received). The spadix is surrounded by the white or coloured spathe. According to Marloth, the whiteness of the spathe is not caused by pigmentation, but is an optical effect produced by numerous airspaces beneath the epidermis.
The genus is restricted to the African continent with seven species recognised: Zantedeschia aethiopica, Z. albomaculata, Z. elliottiana, Z. jucunda, Z. odoratum, Z. pentlandii and Z. rehmannii. The common arum is found from the Western Cape through the Eastern Cape, KwaZulu-Natal, Mpumalanga and into the Northern Province. It is evergreen or deciduous depending on the habitat and rainfall regime. In the Western Cape it is dormant in summer and in the summer rainfall areas it is dormant in winter. It will remain evergreen in both areas if growing in marshy conditions which remain wet all year around.
The rhizome is large and eaten by wild pigs and porcupines and the ripe fruit enjoyed by birds. Traditionally the plant is boiled and eaten. Raw plant material causes swelling of the throat because of microscopic, sharp calcium oxalate crystals. The leaves are also traditionally used as a poultice and a treatment for headaches.
Growing Zantedeschia aethiopica The white arum is very easily cultivated by seed or division. Seed should be sown in spring. The fruit is ripe when it has turned yellowish and is soft. The pulp should be removed and the seed dried off. The grey seeds can be sown in clean seedling mix and covered lightly. Take care not to sow them too thickly as they will need space to form the fleshy roots. The fleshy rootstock can be divided when the plant is dormant, it should be re-planted about 5 cm deep. It may also be propagated by division where the plant is not dormant, use a sharp spade to cut out a section for replanting. The white arum may be used as a marginal plant along streams, or on the edge of a pond. Plant in partial shade if there is no permanent water. It can be planted as a foliage plant in deep shade under trees but will not flower well in this position. It is fast growing and likes very rich, well-drained conditions.
Alice Aubrey |
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Although
called the arum lily, it is neither an arum ( the genus Arum)
nor a lily ( genus Lilium). But it is associated with the
lily as a symbol of purity and these elegant flowers have graced
many bridal bouquets, as seen in this picture of a South African
bride in 1934. 
The
flowers are faintly scented and this attracts various crawling insects
and bees which are responsible for pollinating the flowers. Cross
pollination occurs as the anthers of each flower ripen before the
ovaries. A white crab spider of the family Thomisidae visits the
flower to eat the insects. This spider does not spin webs and uses
its whiteness as camouflage against the spathe. In the western Cape,
a tiny frog Hyperolius hopstocki is also attacted to the
arum lily flowers. The spathe turns green after flowering and covers
the ripening berries. It rots away when these are ripe and the succulent
yellow berries attract birds, which are responsible for seed dispersal.
Zantedeschia
aethiopica grows from 0.6-1 m but may get taller in the shade.
It has lush looking dark green leaves with an arrow head shape.
The size varies according to the amount of shade. The flowers appear
in a main flush from August to January, although there may be the
odd flower at other times of the year also. The white arum forms
large colonies in marshy areas ranging from the coast to an altitude
of 2250m. Thus one will find them contending with humid, salt laden
air at the coast and freezing, misty mountain grasslands at high
altitudes. They are very versatile in the garden as a result. The
leaves of the arum are very interesting in that they contain water
stomata which can discharge excess water, by a process known as
"guttation". This prevents water-logging and enables arum
lilies to grow in wet conditions.
