I bought this plant at a garden show last month and it had a label made from an old yogurt container which simply said "the blue balloon". The lady who sold it to me had a distinct Russian accent and I wondered whether it was a plant which was perhaps familiar to her from her earlier life in that country. This perennial is native to Russia ,east Siberia and other mountain meadows of east Asia. It has just started to flower now and the buds which are greyish blue are more hexagonal than balloon shaped. According to one of my garden books it requires a moist, well drained friable loamy soil and that established plants resent disturbance. Now I just have to find a spot for it and resist the temptation to divide it up for at least a few years. Hopefully it might set a bit of seed in the meantime.