The only problem they suffer from is wind. The branches are very brittle, and have a tendency to break in strong winds. Or when occupied by a Baboon. Or when heavily laden with ripe fruit, as they are right now. On the other hand they seem pretty much immune to the predations of birds and stinging insects thanks to their tough skins.
For some time I have been contemplating growing up a bunch of them to plant as avenue crops further downslope from the veggie garden. This would give us a low-energy-input harvest, and put more of our (sorely under-utilised) land to better use. Low maintenance harvests seem more and more important to me the older I get!
I would like to alternate the Tamarillo rows with Granadillas (which also grow spectacularly well in our soil and climate) and perhaps grain avenues between the rows in Winter. Or possibly interplant the Tamarillos and Granadillas in the same rows! After all, the Tamarillos are much taller, whilst the Grandillas would shade out weeds and grass from the base, and the wire supports needed for Granadillas might help to stabilise the Tamarillos against wind.
The only trouble with this fantasy is that Tree Tomatoes are a relatively unknown crop in SA, and I'm dubious about the idea of producing something that requires me to first educate the market. History shows that the first-mover in such markets almost never makes a success story; that usually belongs to the second comer who enters the already-educated market...
Tamarillos are really easy to propogate. Just sow seed saved from really, really ripe fruit into seed-trays, pricking out into pots or tubes when they reach a size where they're easily handled. I've even had plants self-seed and grow successfully. Transplant into their permanent homes can be as soon as they 15 or 20cm tall. They're not what I would call Long Lived plants, so (like Granadillas/Passion Fruit) I would probably embark on a 3- to 5-year rotation scheme, planting only 1/3 to 1/5 of the total cropping area each year.
We have two different strains of Tamarillo, one being shorter, but I don't see any real advantage to the shorter strain. They don't seem to have been any better at handling wind or fruit loads. I'll probably have to consider planting a wind-break to try and protect them a little.
We use them to make Chutneys and Jams, which are turning out to be really popular barter items at the local weekly swap-meet, since the two of us really cannot consume the fruits of even a single tree. I also munch a whole lot of the fresh fruits while working in the garden, but it hardly makes much of a dent in the crop.
Perhaps I need to buy a Tractor to help with all the work I have in mind... certainly there's much more than I could possibly tackle by hand. I'd probably only hang onto one for a year or two while I carry out all the transformations I'd love to make before selling it on, so I don't view it as a huge money-sink. Hmmmm...