Polemonium caeruleum L.
Polemonium caeruleum L. var. album hort.
Jacob’s Ladder, Greek valerian, Blue Bells, American Greek Valerian
Jacob’s ladder is native to northern and central Europe and northern Asia. It is now naturalized in North America. The name “Jacob’s ladder” refers to the ladder-like spacing of its odd pinnate leaves.
Identification: Plants are up to 20" (50 cm) high. The stem is branched. Leaves are odd pinnate—composed of groups of opposite leaves as well as a leaf on the end of the cluster. The clusters contain 7-11 leaflets. Leaflets are roughly oval-shaped, with smooth edges, about 1½" (3.8 cm) long and ½" (1.3 cm) wide. Large showy clusters of blue flowers appear on top. Flowers are blue, about 1" (2.5 cm) in diameter, with five rounded petals.
Polemonium caeruleum on Wikipedia
Polemonium caeruleum on Henriette’s Herbal Homepage
Polemonium caeruleum in Paghat's Garden
Polemonium caeruleum at Gymnosperms.org
Polemonium caeruleum on Plants for a Future, a resource and information centre for edible and otherwise useful plants
Polemonium caeruleum on Wikimedia Commons
Polemonium caeruleum at the Missouri Botanical Garden
Polemonium caeruleum description by Thomas H. Kent, last updated 12 Oct 2018.
Range: Zones 4-8: