Cyananthus lobatus is a real gem, a gorgeous plant and if you have a chance to get it, or a few cuttings (at this time of year) do so. It has large blue flowers and is happy where small primulas, rhodos etc are happy, cool, damp and humusy, with grit. It is late summer flowering and will set seed but never much, for me at least, and I lost mine a few years ago. It grows from a central mass of stems but they will gradually extend outwards and underground and can be removed well into the clump/mat, to make cuttings. Otherwise, tip cuttings root without much difficuolty.
Cyananthus integer is equally fine and C.microphyllus too, and C, longiflorus ever better, but tricky. There's a yellow from a Chadwell collection also well worth growing but not so good, in my opinion, as the blues. (C. longiflorus is deep violet.) There's a white form of C. lobatus at least, not the others so far as I know.