I also growing illama tree. Here is very cold in the winter season. (-10C)
I think illama don't like to growing in the greenhouse.
When i moved in the greenhouse or room, leaves are dropped and has some black spot like below pic.
Even though summer !!
So i moved in the greenhour or room during winter, make environment like dry season. (Temp 12~13c and little water.No leaves).
Fillany i see flowers first time. Maybe 3 years... but No fruit.