Xref: kermit uk.rec.gardening:158779

I wonder if anyone could help me. I am planning to build a patio with
a pergola over the top. The books I have seen recommend cementing the
upright posts for the pergola in the ground. I am planning to leave
'holes' in the patio to do this (perhaps cementing in the posts and
leaving space for some topsoil above it). The problem I think is that
the soil depth needed to support the root structure of say a clemetis,
might not be enough? Are there any other ways around this. I don't
really want to grow them from tubs or have the pergola structure
outside the footprint of the patio.

I would be grateful for any suggestions.