Polemonium caeruleum Plant Data Family Name: Polemoniaceae Common Name: Jacob's ladder Other Name(s): Polemonium caeruleum Hardiness Zones: Zone 3: (-40 to -34 C) Plant Code: poca Flowering Time: Jun, Jul, Flowering Color: White, Purple, Leaf Form: 3 PlantSomething BC Wholesale Listings No members have selected this plant.