What is ailing my hardy geranium??

[SeratoninIsMyFriend]

This is what I have... Last year it grew furiously with endless blue flowers, with a spread of about 1m almost! This year the leaves have turned rusty brown and are curling up, no sign of further growth or flowers...

It's about three or four years old but only in the ground for two, we're on pretty heavy clay and obviously it's has loads of rain. Nothing else different to last year.

Any ideas?!

[JT05]

Not enough nutrients? The ground looks pretty baren and stoney. I'd fork some compost into the soil around it.