Plant Doctor Archive

Tamarillo won't fruit

I HAVE a very healthy tamarillo - the yellow kind - which is about 2m high with lush growth. While it seems happy in its situation, it flowers but few fruit form. If fruit does form, it turns black and dies when no bigger than a marble. What can I do to solve this?

THIS is a tricky one, as most experts I've talked to say fruit drop is seldom a problem with tamarillos and the tree would probably have to be quite severely stressed for this to happen. Yet it sounds as if your tree is quite healthy.

If it's a young tree the situation may well improve with age. Root problems associated with poor drainage or lack of water in the soil during periods of drought could be the cause, but you'd probably also see symptoms such as drooping leaves and poor growth.

The best approach would be to try to create ideal conditions for fruit formation. Ensure there is good drainage during wet periods - a good dressing of lime or gypsum (1-2kg) around the root area has been suggested by one commercial tamarillo grower to improve soil condition if poorly drained. Mulch with organic material to conserve soil moisture in summer and, if necessary, water during dry periods. Tamarillos like plenty of nutrients so feed in spring with a general fertiliser.

To avoid any possible disease infections, you could spray occasionally. Alternating between Copper Oxychloride and Super Sulphur will control most tamarillo diseases.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.