In article , CK
writes
there are some formulae for the distance over which the windbreak effect
acts - it's a very small number times the height of the hedge, so a 6ft
hedge might not give much windbreak except in its near vicinity

I have just tried to search for those formulae you had mentioned but since
searching.

Try
http://www.cornwall.gov.uk/Environment/trees/advice.pdf

It's a lot better than I thought - total shelter zone 10-15 times
height, though obviously in a slop, so at the end of that zone it's only
sheltered for plants about half an inch high!

Lot of interesting thoughts on that web site, which may or may not have
some relevance to you

We got 2 gaints and loads of young holly in the spilt garden. Maybe we can
try to transplant some of them instead of clearing them.

Good idea. They have long tap roots and are susceptible to drying out
for a few months after transplanting.

from Aberystwyth, Wales

You're milder than we are, being over in the west. Having you seen any
evergreen hedges around you that you particularly like the look of?

Yes, as a town just next to the west coast, the weather of Aberystwyth is
milder than most part of the UK. However, it is the third year I moved in
the town, I am still learning from the neighbouring environment. It seems
that most of the neighbours use either leylandii or privet as hedge.

I like privet - I like the smell of the flowers - but you don't get many
if you keep it trimmed as a hedge.

One
got a mahonia in the mixed border. I got a 3L pot of mahonia and I am
wondering whether I can grow it as part of the hedge. I like the fragrant
winter flowers and the berries would be nice for wildlives.

Native plants tend to be better for wildlife - they move on to the
foreign stuff when they've run out of the rest.
But in a hedge you tend to lose out on flowers and berries unless you
have the space to leave it relatively untrimmed

--
Kay
"Do not insult the crocodile until you have crossed the river"