"jbm" wrote in message
...

"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

Hi. well, I haven't really much choice to put the slabs in and see what
happens. :c)

It's a brute-force method, maybe there are more suptle ways to keep the
roots from coming up 2 foot from the slabs and spreading along the
surface.

Like deception (ingenious watering to fool). Guiding tubes. Whatever.

There ought to be some research reports into this kind of thing - I
suppose.