Mystroxylon aethiopicum “Kooboo Berry” - a tropical substitute for Holly Berries in South Africa

Here is a pretty and uncommon (in the USA) shrub that I thought I'd check out. Mystroxylon aethiopicum or “Kooboo Berry” is native to South Africa. It may have many other common names. I picked this up in October of 2015, so I have not had it long enough to say much. It does not turn up in most of the usual references including no listing in Wikipedia.

To any of our members from South Africa, if you know something about this species. Please share what you know and any photos. I would love to know if anyone has used it for bonsai.

According to my source, it should be protected from temperatures below 32 F (0 C), they did not know exactly how hardy it would be. According to them it seems to produce fruit off and on all year round. When I bought it, it had 3 green berries, they turned red recently, and when I brought it up into the house for photos, 2 berries fell off. They are delicious! I ate them. Though my source says they are supposed to be purple before they are ripe. There was a slight aftertaste, I imagine this would disappear if the berries were purple ripe. Flavor is very sweet, without any tartness, (no or sub acid). Very much like candy, faint caramel note. Mostly just dead sweet. I planted the 2 single large seeds, in the gallon nursery pot the tree is in. Maybe they will sprout. In the foliage there is another couple small green berries just starting to develop. Likely will have more fruit by early spring. So time will tell, but this may be a fun new species for bonsai.





Mystroxylon aethiopicum has a few good traits for bonsai I can identify.
- leaves range between about 0.5 to 2.0 inches, most being less than 1 inch, without doing any of the techniques for leaf reduction. So leaf size won't be a problem.
- it seems to bud back on 2 and 3 year old wood. I don't have any wood older than that, so I can't predict how well it will back bud on decades old wood, but this is good enough to be useful
- seems quite happy in 50% shade outdoors, and has continued to grow in a fairly shady light garden set up of Paphiopedilum orchids (not very bright).
- it is growing well in an ordinary houseplant potting soil - my soil of choice for stock not ready to be called "pre-bonsai" - it should take well to normal deciduous bonsai media, likely will use the same mix I use for maples and elms.
- it is growing even though temperatures in the light garden are between 60 and 70 F.
- growth habit is somewhat generic, like a privet, though it is not related to privet. Should be able to use it for most styles of bonsai. I don't know if it will tolerate being a cascade, but certainly all upright styles look possible.
- only negative is berries are rather large for bonsai, about 0.75 inches. But they are fun to see. For a larger bonsai, fruit could be proportionate.
- I always enjoy the humor potential for bonsai that have edible parts. "Eat your bonsai" is a theme with some humor to it.

Plans for future. I'm open to suggestions. This is just a young plant now. Trunk is about 0.5 inches. It needs several cycles of growing out and cutting back hard before it will be ready to seriously think about bonsai with this plant. I will try to make cuttings, and get them into the hands of others to see if how it behaves under various conditions.

These used to grow in my garden as a kid. I lived on the Highveld - basically at high altitude in a semi-arid environment. Temperatures in winter went down to freezing regularly in winter for up to a week, and there were usually a few frosts over a few very cold weeks. So perhaps slightly less tropical than your research reveals but not an outdoor all year specimen.

We lived on a steep hill and our garden was all rocks, and these grew wild in the rocks when we moved in, and they just stayed there. They are drought tolerant as we did not water them at all and in winter almost no rain falls on the Highveld.

The fruit is slightly sweet, and has an astringent effect that curls your tongue.

The fruit, when thrown at bare legs by your little brother, really stings.

That is great, you are the first to respond that has any knowledge about this species. No replies, nothing but crickets otherwise, including other forums.

I did detect a slight astringent flavor, I thought it might be because the berries I ate were still red, and had not changed to purple. It is possible, that my USA source had stock that had been selected for better fruit flavor, but sounds like the average "Kooboo berry" is not something that would be popular at the produce stand if one were ever to have quantities of ripe berries. Still, I find it an interesting curiosity. I'll grow it a few more seasons, and see if it becomes a "keeper" or only a temporary resident in my collection.

Do you remember what color the berries were when fully ripe?

Do you remember if the bark of the shrub was smooth, or do they develop a rough bark with age?

Did you ever see shrubs with trunks bigger than an inch or two in diameter?

Do you think that if available, it would be a good choice to grow as bonsai?

They only ever grew to shrub sizr, but they were all very exposed and looked rough. I'd say that's the environment not the tendency of the species - I just don't know.

They go very red, and some even a bit purple, when ripe. They are not fruit for a fruit bowl - you nibble on them as a curiosity only.

The leaves are quite glassy and smooth - water retention properties I assume - so i suspect quite hard to reduce their size. But they aren't too big and I'd have a go.

Thanks Brendan
I will certainly give it a go. and keep updating the forum as the tree develops.

- Leo