Emrys Davies wrote:
"Earths_Child" wrote in message
...
[...]
Had some conifers (spreading leylandii) put in early spring to get
a
garden boundary going. [...]

I cut it back, [...]

Why is this happening? Is there anything that I can do to
prevent
healthy looking green conifers from drying out and dying within
what
appears to be days?

I am wondering if you are watering them effectively. Some people
water from a hosepipe or a watering can rose believing that they
have
watered successfully but, more often than not, they will find that
the water runs off the rootball leaving the roots dry.

A dry rootball is hard to penetrate. Water deflects off it. It
needs
to be soaked slowly before planting and then by the application of
water poured directly and slowly onto the roots.

Agreed. But I notice three things. First, you "had" them put in.
People who do these jobs are often pretty clueless and in a hurry.
Perhaps the soil wasn't prepared, and perhaps the roots weren't
gently spread out on planting.

Second, you "cut it back". If you cut back so hard that there aren't
enough leaves left, these trees will die of starvation.

Third, I think you may regret choosing Leylandii. They aren't much
good for making a conventional evergreen hedge (Thuja plicata is
good; yew is excellent but expensive and rather slow), and are one of
the most effective ways to get on bad terms with your neighbours! If
you have no near neighbours and need a quick windbreak for a big
garden, they're great though dull; but even then they'll end up with
bare trunks lower down. If you visit an arboretum and find some old
ones you'll see what I mean. A slow drive round the suburbs being
nosey will show you what they can be like after a much shorter time.

--
Mike.