You don't say where you are, so I can't hazard a guess at what weather conditions you've been experiencing - in the south, we had serious drought throughout May and June and early July - that would affect flowering. I know these flower 'in summer' but I did think they more or less stopped by August anyway.

Sorry, forgot to say that I'm in the south west of Scotland. As it has flowered so well over the last 3 years I know for a fact that this plant can flower right through to November. I just don't understand why it has suddenly come to a halt as it has done so well in previous years - but thank you very much for your reply. I will take into account the weather and hope next year it will improve.

So far as I'm aware, you've had some pretty rough 'autumnal' weather for some weeks now up there.... just like we're now getting here!

It's one of the wonderful things about living in Scotland - we really do get four seasons in one day - but my lovely plant is already used to the inclement weather - maybe it's just rebelling and standing its ground - enough is enough! But thank you anyway.