Words and pictures by Ida K. Rigby, for Let’s Talk Plants! February 2025.

Shepherd's Trees
Our last view of Mashatu in our December 2024 column was of a giraffe emerging from behind a stink shepherd’s tree, Boscia foetida, and passing in front of a huge Mashatu tree.
The stink shepherd’s tree (or smelly shepherd’s tree) is covered with yellow-green blossoms, which, yes, fill the air with an acrid/rancid/sweet odor that some find choking. Boscia refers to the French naturalist Louis A. G. Bosc (l759-1828) and foetida to the odor of the blossoms. The stink shepherd’s tree occurs across the semi-arid regions of southern Africa from Namibia, across Botswana, South Africa, Zimbabwe and through Mozambique.
The stink shepherd’s tree can be either a tree about ten feet tall, a shrub about three feet tall or in the Namib desert a low mat. It is often irregularly shaped with denser branching on one side. Even with a bent trunk, the tree often exhibits the umbrella or mushroom-like shape characteristic of shepherd trees in general.

This shape is in part the result of its growth habit and in part created by topiary artists: Giraffes nibbling at the top and antelopes and livestock browsing the lower branches.

The little group of female impalas is a reminder of why impalas are dubbed the fast food of the savannah: The black replica of the “Golden Arches” inscribed on their rears. These are the “follow me” markings for when a herd scatters in the presence of a predator; members can see where others are fleeing and catch up.

As an aside, my favorite “follow me” markings are the targets on water buck.

In general, the stink shepherd’s trees are more apt to grow up from multiple stems in the eastern part of Southern Africa and a single stem in the western deserts. The multi-trunked habit is represented by the photo of wildebeests passing through a stand of stink shepherd trees in Zimbabwe.

The trees supply sustenance for birds who eat the blossoms and birds, humans and animals who eat the small, round fruit.
Now we’ll fly to Namibia to see the shepherd’s tree, Boscia albitrunca. We last visited this airstrip in Damaraland with its little fire station…

… when we entered the land of the welwitschia (“Welwitschia,” SDHS Newsletter, April 2022) and other desert adapted euphorbias and spiny shrubs.

The shepherd’s tree can inhabit stark desert environments because of its deep tap root.
It is often the lone source of browse and shade in desolate, sandy, rocky terrain.
This landscape harbors the deadly puff adder; fortunately, the one we saw not far from our boots slithered quickly away. Can you find the puff adder in the rocks?

The deepest Bosnia albitrunca rap root recorded, 223 feet long, was in the Kalahari sands in Botswana. In an earlier column we saw the contender for this record, the camel thorn acacia, Vacellia erioloba, in a dry riverbed in Damaraland as we searched for desert habituated elephants.

(“Acacias of Southern Africa,” SDHS Newsletter, August 2023). The deepest camel thorn tap root was measured at 197 feet.
The shepherd’s tree is taller (up to 30 feet) than the stink shepherd’s tree and has a more variegated, gnarled white trunk as distinct from the uniformly gray trunk of the stink shepherd’s tree. Albitrunca refers to the white trunk. Lenticles (raised corky oval areas on branches) allow an interchange of gases with the environment. Its leaves are larger than the stink shepherd’s tree’s and rather than uniformly green are dark green on top and lighter on the bottom. It grows into a compact, very dense form. The shepherd’s tree can live in pure sand whereas the stink shepherd’s tree requires a rocky substrate.
Given the sparse to non-existent vegetation in the Namib desert, the shepherd’s tree is an important food source. Giraffes, gemsbok, kudu and other antelopes browse on the leaves and flowers. Kudu, giraffe and gemsbok eat the fruit. Gemsbok sightings prove that unicorns in fact exist.

The shepherd’s tree got its common name because it is often the only source of shade for herdsmen in the driest deserts. It is often the only source of forage for both wild and domestic animals. Shoots quickly reappear where the tree is nibbled, guaranteeing a continuous source of nutritious leaves as this tree, like the stink shepherd’s tree, is evergreen. The leaves are high in vitamins A and C and protein (14%). As with the stink shepherd’s tree, the browse lines are the result of animals eating the leaves and twigs. Its racemes of small, yellow-green, bisexual flowers are attractive to butterflies, and shepherd’s tree leaves are an important source of food for butterfly larvae.
It is a protected species in South Africa because of its importance to wildlife, cattle, sheep, goats and humans. It, however, taints the milk of cattle that have eaten the leaves. The tree has many indigenous uses. The bark, leaves and roots are used in treating epilepsy, constipation, headaches, hemorrhoids, AIDS, skin diseases and syphilis. (journals.innovareaacaademics.in)
An infusion from the leaves is used to treat eye infections in cattle. The fruit is used in traditional dishes, and flower buds are used like capers in pickles. (The shepherd’s trees are in the caper family [Capparaceae].) The roots are fermented to make beer. Roots are also ground into porridge. The shepherd’s tree figures in traditional lore; for example it is said that if fruits wither before the millet crop is ripe, the harvest will be a failure, and if the wood is burned it is believed that cows will produce only bull calves. (sabi.org—South African
National Biodiversity Institute) Dutch settlers (Boers) used the roots to brew a coffee substitute. Old trees become hollow and store water. During droughts people eat the bark. They make a syrup from boiled roots. Healers use parts believed to have magical qualities. (treesa.org) The heavy wood is used for tables and chairs and for kraals.
In Damaraland, where ground water does exist, farmers eke out a subsistence existence.
It’s one thing, as we saw in the earlier column, for a village along the dry riverbed to turn on their precious water supply to appease visiting elephant herds, …

… it’s another to have them to consume overnight your carefully tended vegetable patch and clusters of dates.
One deterrent is to install solar power fed electric fences.
Elephants do, however, learn to disable them by grounding the wires by propping logs up against them.
Jackals, hyenas and lions regularly stalk this farmer’s chickens and herds. I include this blurry photo of a brown hyena at a water tank, taken from hundreds of feet away, since it was such a rare sighting.

The brown hyena is the one that Mark and Delia Owens (Delia of Where the Crawdads Sing) studied for their classic, Cry of the Kalahari. A lion killed one of this framer’s cows some months ago, and he complained that he was still waiting for the small government payment promised as compensation for lost livestock to prevent famers from killing bothersome animals. The farmer said he would prefer just to be given a cow rather than a meager cash compensation months and months later. This area’s, and this family’s forefathers, were displaced to Namibia from their homes in South Africa in the l970s when the South African government seized their land for military installations.
This farmer makes a weekly donkey cart grocery run. There are a few cell phone hot spots in the general area where they go to call for emergency help.
The village children were playing with a vehicle fashioned from wire and a tiny wooden spool.

Children everywhere play with what’s available; lion cubs in Botswana amused themselves with shepherd’s tree branches.

Now, for a little peek at our next column. The shepherd’s tree will take us to the red sands area of the Kalahari…

… where we will visit Tswalu, a wild lands restoration project in South Africa noted for its accessible meerkat colonies.
There we will meet our guide for the week who told my niece and me his life’s story under a shepherd’s tree. An aardvark happened to saunter by a few hundred feet away.


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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