So, at the Rhine Tribunal in Durenmar, the apprentices won a great challenge and were feted and fed all manner of exotic foods, including oranges.
After the fact, I noted that bitter oranges - the Persian orange - were common in the south of Europe, and were commonly planted. Drat, I think - not exotic!
So, a few centuries later, the sweet orange is introduced from India/Asia. I'm thinking - is it possible that mages might have gotten ahold of the sweet orange as they had dealings in the Levantine States?
Also: the herbam mage kept the pips in the orange. Odds of him being able to introduce the orange a few centuries early via magic?
Ars 5 allows for 'recovery' potions v. 'healing' potions. Anyway our 'recovery' potions taste like Mountain Dew, which is citrus based. So I imagine the inventor got her hands on a orange 'somehow'.
BTW, while we 21st century players may thrive on 'the Dew', our 13th century grogs HATE the taste of the recovery potions as 'the Dew' is essentially more sweet than anything on earth, add carbonation to that and grogs would rather die than drink the stuff. "No! Please! It's like liquid fire glamour!"
That was the income source of our covenant in the first Ars saga I played in, so, why not?
For him to grow orange trees is relatively simple. Auram & Ignem would probably be useful too. And there's story potential, so if he puts some thought into it, let him succeed.
A story to get his orchard started - he probably does not want to spend all his spare time caring for the trees, does he? That means recruiting people that know something about how to care for that kind of trees.
Competition - successful or not ("his exotic fruit trees thrive, mine die off... SORCERY!")
Magical creatures acquire a taste for the fruit and start raiding the orchard (so much more fun than mundane pests).
The spells used to keep the trees alive start warping them.
Incidentally, how's your game going? Anything interesting to relate?