Geography and distribution
The arum lily is native to South Africa (provinces of Limpopo, North-West, Gauteng, Mpumalanga, Swaziland, Free State, KwaZulu-Natal, Lesotho, Western Cape, Eastern Cape), Lesotho and Swaziland. It grows in marshy places from 20 to 2,250 metres above sea level. Although native to Southern Africa it is also widely naturalised throughout the tropics. Description
The arum lily is well known for its striking appearance when in flower, with a brilliant white floral bract wrapping around a yellow finger-like projection in the centre. The flowering parts arise from a ring of glossy green leaves.
Zantedeschia aethiopica is a perennial herb growing up to 60 cm tall (or taller in the shade). It has a thick, fleshy, underground rhizome (swollen stem).
The leaves are evergreen, hairless and form a rosette. The leaves are somewhat leathery, and usually broadly oval with lobes at the base. The inflorescence (flowering part) is on a stalk up to 60 cm long. The spathe (floral bract) is about 15 cm long and 12 cm wide. It is ivory-white on the inside and the outside is bright green at the base and gradually becomes white towards the top. The lower part forms a wide-mouthed funnel, and the much wider upper part spreads out with its tip curled under. The spadix (floral spike) has an upper zone of about 7 cm long, which is covered with tiny bright yellow anthers (male parts). These produce slender threads of white pollen when ripe. The spadix also has a lower zone, which is covered with yellow-green to whitish pistils (female parts) interspersed with mushroom-shaped sterile structures. The fruits are green berries which become soft and orange-coloured at the base when ripe. Uses
All parts of the plant are poisonous, causing irritation and swelling of the mouth and acute gastric diarrhoea. The sap can cause eczema and dermatitis of the skin and is also an irritant to the mucous membranes and eyes. In southern Africa, where the species occurs naturally, the leaves and rhizomes are traditionally used to dress wounds and bites. The leaves and rhizomes are also reported to be eaten, but only following careful preparation to remove the needle-like calcium oxalate crystals, known as raphides.
Due to its striking inflorescences, Zantedeschia aethiopica is very popular as cut flowers and as an ornamental. It is used as a symbol of purity in bridal and funeral flower arrangements.
Scientists have shown that Zantedeschia aethiopica may be useful in artificial wetland systems to clean waste water and prevent algal growth. Cultivation
This moderately hardy monocotyledon can be grown outside in the UK. In any position it will grow best in moist soil or shallow water. In its natural habitat it can be deciduous or evergreen, depending on the rainfall and soil water rather than temperature. The position in which it is planted will also determine size and flowering. Planting under shade is preferable if there is no boggy position for this plant, but this will reduce the number of flowers and result in a smaller plant. Fertile soil is required. In optimum conditions a good display of flowers can be enjoyed in the spring and summer.
Propagation can be by seed or division. Seeds can be removed from the pulp of the fruit when it has turned yellow or orange and soft but gloves should be worn due to the toxicity of the plant. The seeds should then be dried off for sowing in the spring. They should be sown sparingly to allow space for the fleshy roots to form. A seed compost should be used and the seeds covered lightly. Division of the fleshy rootstock should be done when the plant is dormant. It can then be planted at a depth of 5 cm. Millennium Seed Bank: Seed storage
Kew's Millennium Seed Bank Partnership aims to save plant life worldwide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.
Number of seed collections stored in the Millennium Seed Bank: One
Germination testing: Successful Arum lily at Kew
You can see Zantedeschia aethiopica growing at Kew in the Duke's Garden, on the south side by the wall. There are also extensive plantings along the stream in the Secluded Garden, and a large planting of the popular cultivar 'Crowborough' can be seen in the Plant Family Beds.