This grower is sure of this plant identification.
Jacob's ladder, Greek valerian, Charity
Polemonium caeruleum (Jacob's ladder). This species will produce blue flowers which will emerge in late spring and continue into the summer. This plant is often found in the wild in Northern Europe.
They are very frost hardy and easily cultivated in any moist, well-drained soil in sun or partial-shade.
Rock garden Spring/Summer interest.