Its now mid June and this plant has already been in flower, at rosybee, for three weeks and is now approaching its peak. It will keep flowering for at least another 6 weeks and if you 'chelsea chop' a few stems it will produce some secondary flowers that will keep blooming till the end of August.
I planted 10 plugs last spring (I probably put them a bit too close) and they have now formed a single clump about 1.5 m across at 1.2m high. Some of the individual blue spires are almost 40cm long and each day a new series of flowers opens higher up the stem to provide fresh nectar.
It attracts a wide range of short tongued and longer tongued bees. I have noted all of these over the last few days: honeybees, garden, early, buff-tailed, tree bumblebees as well as butterflies and a few solitary bees.