The Simple-leaved Rhigozum (Rhigozum brevispinosum)

•Luise HoffmannAFTER the first rains, this otherwise quite inconspicuous shrub bursts into a spectacular show by being completely covered in golden yellow trumpet-shaped flowers.

It is an erect shrub up to two metres high occurring mainly north of a line connecting the Naukluft Mountains and Leonardville and only occasionally further south. When in flower it can be seen on the hill slopes next to the B1 just south of the bridge over the Swakop River near Okahandja. It is also quite common north of the Omatako Mountains and in western Etosha and seems to prefer chalky soils.

Names: G. Kurzdorn A. wilde granaat, kortdoring-granaat H. omunditi, omuporapingo. The generic name Rhigozum means ‘stiff twigs’ while brevispinosum refers to the short thorns.

Straight spines, about one centimetre long, grow at right angles to the twigs. The bark is grey-brown and smooth. Small narrow leaves, up to 5 mm in length, are mostly clustered on dwarf shoots originating from tiny woolly cushions immediately below the thorns.

The shrub can be identified by these woolly cushions all year round. The lovely flowers develop into flat, two-horned, pale grey-brown capsules about 7 cm long and pointed at both ends. When ripe they split open to release numerous seeds.

Game and livestock browse on the young shoots. In the Kalahari the tough branches are used to dig up nutritious or succulent roots and bulbs. Reportedly the Otjiherero name “omuporapingo” means ‘makes the heart jump with happiness’ referring to the striking beauty of the shrub in flower. The simple-leaved rhigozum makes a very decorative drought and frost-resistant plant for large gardens and parks. It can be propagated by fresh seed and by its underground rhizomes.

Three-thorn Rhigozum (Rhigozum trichotomum)

The three-thorn rhigozum is covered in white or pale pink trumpet-shaped flowers soon after the first rains, not quite as showy as its simple-leaved relative described above but beautiful nevertheless. This shrub is easy to identify at any time of the year because its young branches terminate in three shoots at the growth points. It is mainly found in the southern half of Namibia and only occasionally further north.

Names: G. Dreidorn, A. driedoring H. okatakambindu. The Otjiherero name indicates that the three-pronged branches arre used to vigorously stir blood of a slaughtered animal to prevent it from coagulating.

The spinescent branches are covered with small simple leaves spirally arranged or clustered on dwarf shoots.

The two-horned capsules are 4 – 5 cm long, pointed at both ends and remain on the plant for some time.

The leaves and flowers of three-thorn rhigozum provide excellent fodder for small-stock, especially since the shrub sprouts green leaves very soon after the fist rains.

According to reports by someone who as a boy looked after his father’s sheep each flower contains a drop of very sweet nectar, which he liked to suck. However, the flower itself has an extremely bitter taste, which sheep do not seem to mind. They are very partial to the flowers, which increase their milk-yield but also give the milk a bitter taste.

The three-thorn righozum is propagated by seed and by underground rhizomes. It may become invasive forming dense thickets on disturbed soil as can be seen along the B1 south of Rehoboth and along other roads in the south-western regions of Namibia.