There is no rush as the old stems will provide a little protection from any late frosts. Wait until new growth is established at the base of the plant. I only have one showing new growth so far down here in the SW so yours will probably be quite a while yet.

I agree with that,too,Sally..and as you are much further North,it could be a lot later than mine..we are in .Yorkshire,and it's usually around end of April,into May..I guess it's dependant on the weather,even if it is a hardy one..