We inherited a really large hydrangea @MarieMartin in out new garden. I cut it back almost to the ground in the first spring, it grew well but no flowers in the first year. This year it has been superb with lots and lots of beautiful flowers. Next spring I will just deadhead and prun back lightly to keep a good shape.
Thanks for the advice about my hydrangea Joanboston, I'll make sure my son doesn't deadhead it until the springtime, he's coming up to Surrey to see me tomorrow. If I find the photo I will post it, when I know how to....... x