Hello,
I've done the Google searches but I didn't really find any information
that fits what I am trying to do.
I have excavated 3 feet of soil for a sunken "courtyard" and I plan on
using the Anchor Diamond interlocking blocks as the retaining wall.
The edge of the wall comes within 8 feet of several Mulberry trees and
while digging I had to hack through a small number of roots, the
largest being about thumb sized. These trees are currently about 15
feet tall (small). If you draw a circle with the edge 8 feet from the
trunk, the wall will occupy maybe 1/4 of the circle. My concern is
that the roots will want to mess with the wall.

My plan for the wall is basically standard. 3 foot wall with about 12
inches of gravel backfill with the gravel seperated from the dirt with
landscape fabric. There should be plenty of drainage and the soil is
very dry (central NM). I am thinking that the gravel and landscape
fabric will not hold back root growth. My thought is to place
corregated steel roofing panels directly behind the wall blocks to
hopefully guide the roots downward should they happen to reach the
wall.
Is this nuts? Is there a better way? Am I being too paranoid about the
roots in the first place?

Thanks!

-Bruce