I'll be interested to hear the answers - as I pruned in Autumn and am just pleased the plant survived my efforts at pruning. It is looking a bit spindly, so if it possible to give in another trim now, I would like to do that.

Hack it back whenever you like, as much or as little as you want - it does tend to be a spindly plant I find, so I'm always lopping bits off it throughout the summer, and this isn't a problem unless you particularly want the flowers.

This is only the second year I've had mine so I'm interested to see the flowers - but good to know you can chop it when you like. It is a very spindly plant isn't it - does it always shoot from the old wood as mine seems a little bare at the base? It also seems to do a lot better in shade which I didn't realise initially.