Actually I suppose part of the charm for an Italian reader in reading a
book set in South Africa is to encounter all the exotic place and plant
names

Jie-san Laushi schreef
Okay, so you're saying, just stick the English word Yellowwood into an
otherwise Italian sentence?

+ + +
Yes, does not seem too bad, does it?
+ + +

I just had another idea: if this book is set in South Africa, why not try
to find out the Afrikaans or Zulu names, and use those?

Jie-san Laushi

+ + +
That might work. Depends very much upon the perspective of the book.
English settlers, Afrikaander, or local people? The Afrikaander names are
readily available (yellowwood = geelhout, likely the english is a
translation from the Afrikaans), but there are very many local people
involved with very many different languages. This might get very involved
very easily.
PvR