Many years ago someone put a shrubbery in our garden. It had weed
control fabric, and I suspect a layer of bark chipping over the top.

I've just moved one of the shrubs - it is now overshadowed.

The bark mulch has mixed with many years of leaves to make a couple of
inches of quite nice compost. The shrubs have spotted this, and put
roots in it. There are also a variety of smaller plants growing in it.

Underneath the fabric the ground is clay. It's had no worm activity in
years, and has set to a hard pan similar to subsoil.

It took me nearly an hour to dig out one small shrub (roots 50cm across,
20cm deep) followed by having to tease out the weed control fabric
layer. It's no longer completely root proof, and there are some roots
going through it.

Andy