What's killing my hydrangeas

Hi folks, I noticed the other day both my hydrangeas appear to be dying. They were doing fine and have done for years, i pruned them as usual and had lots of new growth on them and now all the leaves are turning brown and shriveling up. I've read there can be fungal infections that affect them but this doesn't look like one. There's no spotting or furring up just the tip of the leaves has dried out and died, Any help on this gratefully received.

Thanks.

Sounds like the young growth has been hit by a frost. You don't need to do anything, they will produce new leaves in time.

Hi, thanks for the reply, it does look a little like frost damage except we haven't had any frost here since before i pruned it. Any idea what else it could be?