Hydrangeas

[FuzzyCustard]

What do I do with my mop head hydrangeas in the Spring? I have left the flower heads on all winter and I think I've got to trim them off a couple of buds down. Is this right? And when?

info here

They are quite 'hardy' care wise - I in my innocence chopped ours back at the wrong time, it didnt flower the next year but came back the year after

Cheers furball. I think I may have chopped mine a bit enthusiastically last year - they had a few flowers but not many in the summer and I'd like to see them be a bit more prolific. (They are practically the only inherited plants in this garden!)