"Rich" wrote in message
...
| 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.
|

Hmmm. Sounds a good idea, as I thought about 15 years ago. There are a load
of Forsythia (I think) bushes outside my garden, so I did exactly what you
have in mind, sinking 2'x2'x2" slabs vertically across the bottom of my
garden. Complete and utter waste of time. I managed to keep up with the
roots that came between the slabs, but the other day, the dog, during one of
her open cast mining exercises on the lawn, managed to dig up one rather
large root (almost 1" dia) that had migrated under the slabs and back up to
the surface within 2' of the fence. Sub-surface under the lawn is ironstone
brash. I guess you're on a hiding to nothing there.

jim, Northampton