Words and pictures by Ida K. Rigby, for Let's Talk Plants! October 2024.
Kalahari Desert Shrubs
So far, most of our botanical encounters have taken place in the "sand sea" (360,000 square miles) that is the Kalahari Desert. The sand sheets were laid down in the Pleistocene Epoch and are all over two hundred feet deep. The sands can be a neutral color (note elephant footprints) or red due to oxides.
Technically the Kalahari is not a desert as it gets too much rain (5 to 10 inches), but the water quickly passes through the sand and no surface soil accumulates. (kalaharidesert.net) Soil cyanobacteria create nutrients that allow grasses to grow for semi-subsistence farmers’ cattle and wild grazers. These bacteria are drought resistant and fix atmospheric carbon dioxide, which can help mitigate global warming. (sciencedaily.com)
One of the most characteristic shrubs in southern Africa is the wild sage or stink bush (Pechuel-leubnitziae).
It is becoming increasingly prevalent as it quickly takes over areas that have become dry with the persistent drought. Wild sage was named after the German plant collector Eduard Peuchuel-Loesche (l840-1913). Initially it is a gray green, then as it dries out the leaves turn golden, and the flowers become feathery seed pods.
Note the “follow me” white flag on the tails of the African wild dogs (painted wolves) disappearing into the wild sage and the yellow leaves of the mopane trees. When dry the shrub creates highlights, which create lovely photos.
It is found in a variety of dry, sandy habitats including open areas and woods. It thrives in disturbed areas, which made it a beautiful backdrop one evening as we followed two lion brothers starting an evening patrol of their territory.
We had just stopped at a crossroads for our evening sundowner.
As we got back into our 4x4 the two brothers came around the curve in the road behind the vehicle, moved into the shrubbery to our left to pass us and headed up the road. Had any one of us been doing what often happens during breaks, answered the call of nature behind the vehicle, the lions would have come upon the person, very abruptly. I asked Richard what would have happened. He simply said they might have gone around or . . . He changed the subject by challenging us to point in the direction of our camp. We were all way off. Then he asked if we were stranded and knew the direction home would we try to go cross country or follow the road. We all enthusiastically said, “follow the road.” His answer was, “let’s see.” We spent the next 45 minutes following the brothers and as they carefully followed the road. Only once did they cut cross country, but that was because the road took a wide curve, and they knew they could rejoin it by going straight through the bush. Lions follow the easiest path, too, a road.
Another frequently encountered shrub is the bushveld bluebush (Diospyros lycioides).
The plant has bluish leaves; male and female flowers appear on different plants. The fleshy, red berries are eaten by birds, dassies (rock hyrax—which according to their DNA actually share a distant relative with elephants and manatees) (sand.org), monkeys and humans.
People use the berries for alcoholic beverages and the seeds to brew an ersatz coffee. There are many medicinal uses, including chewing roots to treat colds and taking powered bark as an abortifacient. Roasted and powdered roots are mixed with mutton fat to make a plaster to ease aches and pains. On one of our bush walks our guide snipped off twigs of a bluebush so we could try the indigenous practice of using the shrub’s twigs or roots as a toothbrush and tooth whitener.
Bluebush wood is used to build huts and make spoons, and the bark is used for tanning skins. (herbgarden.co.za and pza.sanbi.org) Bluebush thickets appear to be convenient places to hide or picnic behind. That’s deceptive. Look at the left corner of the bluebush. The females of the local pride had stashed 6 of their cubs in its shelter.
The knobby creeper (Combretum mossambicense) grows as a shrub, small tree or vine.
I include four photos because they illustrate both the knobby creeper and one of the most endearing behaviors of young male elephants (tiny tusks indicate his age). They think they are hidden by the most modest of covers and peak out, then cautiously emerge from their “hiding” places. Mom is never far away, which gives them courage. A slightly older male who would soon leave his natal herd played peek-a-boo with us from behind a young knobby creeper.
The young males seem to think that if one eye is covered you cannot see them. Later that day we encountered a more formidable presence. Mom was not somewhere nearby in the thickets, but right by the road. As her youngster fled, she flared her ears, stomped her feet and swung her trunk to let us know she was not pleased with our presence.
The knobby creeper produces little puffs of cream or pinkish flowers from August into November.
Insect pollinators visit the flowers and attract insect-eating birds such as the brown-hooded kingfisher. The flowers become winged fruits and then papery seed pods. The leaves of the knobby creeper have medicinal uses when mixed with Acalypha villicaulis and boiled in water to steam the face to treat tooth abscesses or eye inflammation. The dregs are turned into hot compresses. (pza.sanbi.org) Browsing mammals enjoy the leaves. Graceful giraffes nibble on the flowers with their delicate lips and sensitive tongues.
"Tsamaya sentle"
(Which translates, "Go well" in Setswana, the language of Botswana.)
Ida Rigby is a past SDHS Board member and Garden Tour Coordinator. She has gardened in Poway since l992 and
emphasizes plants from the northern and southern Mediterranean latitudes. Her garden received the San Diego Home/Garden magazine Best Homeowner Design and Grand Prize in their Garden of the Year contest in l998. Her travels focus on natural history.
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