In article , rob w
writes
We have at the bottom of our new garden a very old hawthorn hedge,
this is very thick and quite tall but the bottom 3 to 4 feet is bare
and quite open.
It would be very easy to crawl through. My question is can this hedge
be thickened up or should I remove and replant, I have heard of laying
it over but the bottom trunks are very thick and I’m not sure if
this will work.

Get and expert in to lay it.

If you want to renovate it yourself, it'll take a year or two. Hawthorn
shoots quite readily from bare wood, so what I would do (and am doing on
mine with signs of success) is reduce the height of the whole thing
though not so low as to be below the current green bit. Then on
multistemmed plants take out one or two trunks quite low, and try with
any that are convenient cutting them half or 3/4 through and bending
them to lie sideways.

Your aim is to encourage shooting down below by removing top growth, and
to allow enough light into the bottom for that new growth to flourish.
--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/edward/index.htm