Sorry, no, there's nothing you can do - if they're weeping at the base, they'll need to be taken right down, but you might find they shoot from below the ground later on if you don't remove the roots.

Thank you for this. It is with great sadness that I will have to cut them down. They are beginning to look pretty bad now. Hopefully, new life will emerge at some time. Thanks again. cmj.

If its any comfort, you won't be alone in experiencing such a loss this year.

Exactly the same happened to mine last year. I was so upset. I had had them for so long and they were huge. Some I cut down, others I dug up and have kept them in an out of sight place. Some of them started to regrow from the base last summer though none higher up which I have had once before. Sadly this winter has finished the new growth off even though they were fleeced.