Rich wrote:
The ground surface behind the 5 foot high stone wall in the back of
garden is about 5 foot higher than my garden surface. The wall was built
on a 3 or 4 inch foundation of broken stones. There was no cement put
into the foundation.

Tree roots from the ground behind the wall (there's a line of quick
growing conifers about 4 foot behind the wall, and there's a Finish
White Beam and a tall Poplar tree) have squeezed under the foundation
and then proceeded to fan out over the surface of my lawn and damaged it.

Below about 4 or 5 inch of the ground surface I have sandy stony ground.

I'm redoing the lawn and the wall. I'm going to keep the old wall in
place, and put a brick wall in front of it with a proper cemented
foundation. This new wall will be spaced about 2 inch away from the old
wall.

I've got some pavement flags (slabs) 2 goot by 2.5 foot, 2 inch thick.
I'm going to put them in the ground adjacent to the base of the old
wall, with about 6 inch sticking up above ground surface. So, the flags
will penetrate 1.5 foot below my ground surface just in front of the old
wall. Then I'll fill the 2 inch gap between the walls with stones.

Okay, is this going to divert any roots downwards from under the old
wall, into the sandy rocky soil and stop roots growing on the surface of
my lawn? TIA.


Hmm..... Quite challenging; sounds like your trees are busily heaving
your 5' earth retaining wall out of their way, this probably will get
worse as time slips by. You might find that that your new wall section
might start going the way of the old sooner, rather than later

The cheapest permanent solution might well be to eliminate the wall
altogether by terracing out the 5' drop in levels - if you have got the
space and energy so to do.

Another solution could be to take out the wall and replace it with a
line of gabions filled with the stone salvaged from the wall + some
bought in rock. Quit a costly solution, a standard 1x1x1 metre basket is
about £40 and needs about a tonne of rock to fill it, but the benefit is
a very robust free-draing revetment with a very dramatic planting
evironment for alpines and climbers. Hard work but alot of fun to do and
the results can look good and likely to be tree root proof for decades.

Good luck

rjbl