Plant of the Month for October 2013

Polemonium pulcherrimum
Polemonium pulcherrimum

Description and general information:

Polemonium pulcherrimum or showy Jacob's-ladder, is a tufted plant, to 30 cm, with erect to decumbent stems. Leaves are pinnately divided into 9–21 widely oval to round leaflets. The plant has a skunky smell when bruised.  Flowers are produced in terminal clusters. Individual flowers, about 2.5 cm across, are saucer-shaped and have five blue petals fused at their base.  The center of the flower is yellow. 

Plants are found in the subalpine and alpine zones (about 8,000-11,000 feet) of the western US, Alberta, BC, Yukon and Alaska, growing on gravelly soils and talus slopes.


This species requires full sun in northern areas but light shade in hotter regions. If exposed to drought, plants may go summer dormant or possibly die.  Moist but well-drained soil is ideal.  If kept reasonably moist, plants will bloom throughout the growing season. Alkaline or neutral soil is best.

Bloom period:

In the wild, this species blooms late May through late July.  In milder climate, flowering commences in late March while in more northern regions, May-June is the normal flowering season.


Seed, division, cuttings


Seeds require light for germination so surface-sowing is required.  Ontario Rock Garden and Hardy Plant Society suggests seeds may be directly sown at 20 C and germination will occur within 3 months. Stratification is not required.


Larger plants could potentially be dug and divided in early spring or late summer.


A piece of rhizome with a tuft of leaves, may be used as cutting material.

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