Zantedeschia aethiopica (L.) Spreng.

Common names:White or common arum lily (English); Wit varkoor (Afrikaans); intebe (Xhosa) ihlukwe (Zulu)
Family: Araceae (Arums, Anthurium, Caladium and Philodendron)

Zantedeschia aethiopica

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.Bridal bouquet 1934Although 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.

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.

Insects inside the arum lily.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.

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.

Leaves of arum lilyZantedeschia 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.

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 on the margins of a pool.

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.


References:

  • Batten, A. 1986. Flowers of Southern Africa. Frandsen Publishers. Sandton.
  • Du Plessis, N & Duncan, G. 1989. Bulbous Plants of Southern Africa: A
    Guide to their Cultivation and Propagation
    . Tafelberg.Cape Town.
  • Jackson,W.P.U. 1986. The Cape white arum lily, Zantedeschia aethiopica in Veld& Flora 72:44-45
  • Letty, C. 1973. The Genus Zantedeschia. Bothalia 11, 1&2: 5-26
  • Joffe P. 1993. The Gardener's Guide to South African Plants. Delos. Cape Town
  • Pooley, E. 1998. A Field Guide to Wild Flowers of Kwazulu-Natal and the
    Eastern Region
    . Natal Flora Publications Trust. Durban
  • Van Wyk, B-E, van Oudtshoorn, B & Gericke, N. 1997. Medicinal Plants of South Africa. Briza Publications, Pretoria.

Alice Aubrey
Witwatersrand National Botanical Garden
With additions by Yvonne Reynolds
November 2001


SANBI Home