Pelargonium sidoides DC.

Common name: Kalwerbossie, Rabassam
Family: Geraniaceae

Pot of P. sidoides in foreground

P.sidoidesPelargonium sidoides forms a rosette-like plant with crowded leaves. It is very similar to some forms of P. reniforme, but is easily distinguished by its blackish, rather than pink petals. The long-stalked leaves are mildly aromatic, heart-shaped and velvety. The distinctive dark, reddish-purple (almost black) flowers are present almost throughout the year, but occur mostly from late spring to summer (October - January) with a peak in midsummer (December). The genus name Pelargonium is derived from the Greek word Pelargos which means stork. This refers to the rostrum of the schizocarp (seed capsule) which resembles the bill of a stork. The species name sidoides reflects the resemblance of the foliage to that of a European plant, Sida rhombifolia.

Pelargonium sidoides has a wide distribution. It occurs throughout the eastern Cape, Lesotho, Free State and southern and south-western Gauteng in the Republic of South Africa. It usually grows in short grassland and sometimes with occasional shrubs and trees on stony soil varying from sand to clay-loam, shale or basalt. P. sidoides is found at altitudes ranging from near sea level to 2300m in Lesotho. It is found in areas which receive rainfall in summer (November to March) varying from 200 - 800mm per annum.

P.sidoidesThe plant is an evergreen in cultivation, but it probably dies back in nature during droughts and in winter (May to August). The system of thickened underground root-like branches is a special adaptation which enables the plant to survive grass fires which occur almost annually over much of its range.

P. sidoides can be planted in rockeries in full sun. It is also an excellent pot plant. It is utilized for a variety of folk-medicinal purposes resulting in the colloguial name 'Rabassam'.

Growing Pelargonium sidoides

P. sidoides experiences moderate, rather than high, summer temperatures and winter frost or even snow over much of its range. This plant needs less water during winter and watering should be increased at the beginning of summer (November to March). Top dressing with a slow release fertilizer in spring will improve growth and flowering in summer. In winter, dead leaves and old flower stalks should be removed from the plant.

This plant is easily propagated from seed or by means of basal cuttings in autumn (March to May). The cuttings should be prepared and the base dipped in a rooting hormone and then be placed in containers with coarse riversand which has been pre-watered with a fungicide. The containers with cuttings should then be placed in cold-frames to root. If plants are kept in glasshouses, yellow sticky traps should be placed strategically to combat white-fly.

The family Geraniaceae consists of five genera; Geranium, Erodium, Monsonia, Sarcocaulon and Pelargonium. The genus Pelargonium consists of more than 200 natural species. The larger majority occurs in South Africa, while a few species occur in tropical Africa, Syria, Australia and on a few islands in the Indian Ocean. About 80% of the South African species are confined to the winter rainfall south-western Cape.

For more information see: Van der Walt J.J.A. & Vorster P.J. Pelargoniums of Southern Africa. Volumes 1 and 3.

Ebrahim Lawrence
Kirstenbosch Botanic Garden
May 2001

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