Stan The Man wrote:
[...]
I'm vaguely thinking about a matrix of railway sleepers in
the shape of a crossword puzzle which would enable me to tend the
bog
garden while also helping it to look intentional.... I guess that
the
plants would eventually obscure them anyway.
[...]

Beware slipperiness, though. Stapling chicken-wire over the sleepers
will give a bit of grip, and is pretty nearly invisible.

Mike.