I agree, this is a great way to train fruit trees. In the northern
rockies we paint our trees, not lemons of course, to reduce the winter
sun burn, but planting next to a building, to espalier, protecting the
trunks becomes a summer burn issue. You might try planting shrubs or
tall perinneals on the sun side.
Steve

figaro wrote:
I was just looking through a mediterranean gardening book and saw a picture
of this being done. Interesting. They mentioned two points; make sure your
arbor has wide enough openings to let the lemons hang down for picking and
whitewash the bare trunks to prevent sunscald. I thought about trying this
until I saw the whitewash part. I hate that look. I guess you could also
use some other sort of trunk wrap.