In article , David@chapelllllh
ouse.demon.co.uk writes
In article , Dave Painter
writes

Leylandii, do not grow from old wood so lopping the top off will cause the
trees to die back.
This either isn't true at all or is rare, I've seen many trees cut back
severely and continued to grow well

They don't generally grow back from old wood, but they won't die back
further just because you've chopped them. We took about 10ft of the top
of ours last year with no problem.

They need to be trained from an early age, regularly and frequently.
Agreed, for best results

If they are 20 foot now you should be able to take off about two foot, then
in three or four months
take another foot off.
I took 9' off my neighbours in one go without any ill effects and the
trees continued to grow

Then you will be looking at taking new growth off every three months.
Only during the summer of course

And it doesn't need to be that often. Ours has about two foot of green
growth horizontally, so I could cut it back at least a foot with no
problem. Though if I kept it trimmed back, I suppose I might have a lot
less, and would have to trim it more often. But I'd sooner trim a nice
soft leylandii 3 times a year than a hawthorn once a year!


--
Kay Easton

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