fig or feijoa or pomegranate?
I have a very unique microclimate I want to make use of to grow something marginally hardy for my zone 7. The south end of a block building is 12' wide and has a cold frame attached to it that's about 3-1/2' tall that I add glass to and use from February to early May. I'd like to plant something in the cold frame that could grow straight up out of the cold frame and then would start branching above the cold frame, preferably closer to the wall. Since the feijoa is evergreen it would have to be trained very close to the wall so as not to shade the plants in the cold frame. Which of the three plants could best be trained straight up to 3-1/2' and then be more or less espaliered (i.e. kept reasonably tight against the wall) to fill the remaining space up to 8' tall (about 12' in the middle) and 12' side? Would the artificially warm glassed area at the base of the tree cause problems? I have limited sunny, south-facing walls, so I'd like to make use of it if I can. What about a satsuma with some kind of added protection (like a big blanket draped down from the roof of the building) on the coldest nights?