On Sunday, 7 April 2013 17:58:49 UTC+1, wrote:
I cut them back to 3' in the autumn, but they have suffered badly.

They aren't dead, but most of the live shoots are near the top.

My concern is that, if I cut them back into very old wood, they

may not survive it. If I don't cut them back hard, they will

get out of hand. Any comments?





Regards,

Nick Maclaren.

Leave it alone for now - It won't get out of hand this year, but in any case it won't be too late to prune it when you see where the new growth comes from and you'll be able to prune out any damage.
I assume we're talking about the 'davidii'' group that flower on current years growth rather than things like B.alternifolia that flower on the previous years growth.

Rod