This grower is sure of this plant identification.
Original pant was split
Geranium himayalense (Lilac geranium). The flowers are the largest of any species of geranium they are lavender-blue and have a reddish centre with rust-purple veins. The blooming period is long, from 4 to 6 weeks and the leaves will provide some nice autumn colour before fading in the autumn.
Constant moisture is required for best performance and they should be divided every 2 or 3 years.