For the identification of insects and other fauna and flora of South Africa.

Tuesday, August 20, 2013

Ginger Bush (Tetradenia riparia)

Family Lamiaceae
It is cultivated for this spectacular show which occurs when there is not much else in flower. The flowers range from white to lilac including some with pink flowers. The type of display which you will get depends on whether you have a male or female plant! Male and female flowers are borne on separate plants in spikes which differ in size and shape. The male flower spikes in profusion create more of the "mist" effect than the female flowers which tend to be more compact. The flowers usually appear when the plants are bare and are carried in the top section of the branches. Flowering occurs from June until August which coincides with the frosts in Highveld gardens. The flowers may be spoiled by this so it is a good idea to plant the ginger bush in a warm spot such as against a north-facing wall or on a succulent rockery.
The ginger bush is a tall, aromatic shrub up to 3 m in height, occasionally reaching 5 m. It is slightly succulent and has an irregular branch pattern. The stems are brown and smooth, except for the younger portions which are covered with glandular hairs and have a ruby tinge. The glandular hairs also cover both surfaces of the leaves and make them slightly sticky to the touch. The leaves are a bright green and are slightly heart shaped with the margin irregularly and bluntly toothed. Like many Lamiaceae species (which includes familiar culinary herbs such as thyme, sage and rosemary) the younger branches are distinctly four-angled in cross section. The ginger bush is no relation of the true ginger plant of which the underground stem is commonly used for flavouring and in preserves.
The natural habitat of Tetradenia riparia is along river banks, forest margins, dry wooded valleys and hillsides in areas where there is little frost. The natural distribution ranges from KwaZulu-Natal, Northern Province, Mpumalanga in South Africa to Swaziland, Namibia, Angola and northwards through tropical east Africa into Ethiopia.