I am thinking of planting a 6 foot high fedge around the perimeter of
our garden, to act as a wind break. There's already a low (3 or four
feet high) dry stone wall all the way around, behind which I'd like to
insall the fedge. How close to wall can I plant the fedge? - I want to
avoid the possibility of the roots of the fedge eventually causing the
wall to become unstable.
Factors:
a) I am very short of space, and want to get as close to the wall as
possible
b) The soil is not to heavy, not too light, and although we get plenty
rain (west coast of Scotland), it is not water-logged.

Thanks, in advance!