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Polemonium boreale (Northern Jacob's ladder)

Beginner
skill rating
1 hour care
per year
0.3m
Max height
0.4m
Max spread
2-5 years
To maturity

Plant details

Botanical name

Polemonium boreale

Other names

Northern Jacob's ladder, Arctic Jacob's ladder, Boreale Jacob's ladder, Polemonium boreale 'Blue Whirl', Polemonium boreale 'Bambino Blue', Polemonium boreale 'Azuro', Polemonium boreale 'Blue Swirls', Polemonium boreale 'Blue Pearl', Polemonium pulcherrimum, Polemonium richardsonii, Polemonium pulcherrimum 'Tricolor', Polemonium viscosum 'Blue Whirl'

Genus

Polemonium Polemonium

Species

P. boreale - P. boreale is a compact, clump-forming, herbaceous perennial with pinnate leaves divided into numerous small, oval to oblong, dark green leaflets and, in summer, upright, branching stems bearing panicles of light violet-blue flowers with yellow eyes.


Polemonium boreale is: Deciduous

Habit

Clump-forming, Compact

Flower

Violet, Blue in Summer

Foliage

Green in Spring; Green in Summer; Green in Autumn

How to care

Watch out for

Powdery mildew Powdery mildew

General care

Pruning

Deadhead regularly. If becoming untidy, cut back by half in midsummer to rejuvenate. Cut to the base in autumn.

Propagation methods

Division, Seed


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Where to grow

Polemonium boreale (Northern Jacob's ladder) will reach a height of 0.3m and a spread of 0.4m after 2-5 years.

Suggested uses

Beds and borders, Cottage/Informal, Low Maintenance

Cultivation

Grow in gritty, moist but sharply-drained, preferably neutral to alkaline soil in sun or partial shade. Needs consistently moist soil in growth but avoid waterlogged conditions in winter. Needs afternoon shade in areas with warm summers. This species is often incorrectly sold as a number of different cultivar names.

Soil type

Chalky, Clay, Loamy, Sandy (will tolerate most soil types)

Soil drainage

Moist but well-drained

Soil pH

Alkaline, Neutral

Light

Partial Shade, Full Sun

Aspect

South, East, West

Exposure

Exposed, Sheltered

UK hardiness Note: We are working to update our ratings. Thanks for your patience.

Hardy (H4)

Companion plants

We do not currently have companion plants added for this plant.

Botanical name

Polemonium boreale

Other names

Northern Jacob's ladder, Arctic Jacob's ladder, Boreale Jacob's ladder, Polemonium boreale 'Blue Whirl', Polemonium boreale 'Bambino Blue', Polemonium boreale 'Azuro', Polemonium boreale 'Blue Swirls', Polemonium boreale 'Blue Pearl', Polemonium pulcherrimum, Polemonium richardsonii, Polemonium pulcherrimum 'Tricolor', Polemonium viscosum 'Blue Whirl'

Genus

Polemonium Polemonium

Species

P. boreale - P. boreale is a compact, clump-forming, herbaceous perennial with pinnate leaves divided into numerous small, oval to oblong, dark green leaflets and, in summer, upright, branching stems bearing panicles of light violet-blue flowers with yellow eyes.

Native to

North America, Northern Asia, Northern Europe

Foliage

Deciduous

Habit

Clump-forming, Compact


Colour

Flower

Violet, Blue in Summer

Foliage

Green in Spring; Green in Summer; Green in Autumn


How to care

Watch out for

Specific diseases

Powdery mildew

General care

Pruning

Deadhead regularly. If becoming untidy, cut back by half in midsummer to rejuvenate. Cut to the base in autumn.

Propagation methods

Division, Seed


Monthly care advice


Where to grow

Polemonium boreale (Northern Jacob's ladder) will reach a height of 0.3m and a spread of 0.4m after 2-5 years.

Suggested uses

Beds and borders, Cottage/Informal, Low Maintenance

Cultivation

Grow in gritty, moist but sharply-drained, preferably neutral to alkaline soil in sun or partial shade. Needs consistently moist soil in growth but avoid waterlogged conditions in winter. Needs afternoon shade in areas with warm summers. This species is often incorrectly sold as a number of different cultivar names.

Soil type

Chalky, Clay, Loamy, Sandy (will tolerate most soil types)

Soil drainage

Moist but well-drained

Soil pH

Alkaline, Neutral

Light

Partial Shade, Full Sun

Aspect

South, East, West

Exposure

Exposed, Sheltered

UK hardiness Note: We are working to update our ratings. Thanks for your patience.

Hardy (H4)

USDA zones

Zone 8, Zone 7, Zone 6, Zone 5, Zone 4

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This plant likes... Garden match
Soil types: Chalky, Clay, Loamy, Sandy (will tolerate most soil types) Tell us...
Soil drainage: Moist but well-drained Tell us...
Soil pH: Alkaline, Neutral Tell us...
Light: Partial Shade, Full Sun Tell us...
Aspect: South, East, West Tell us...
Exposure: Exposed, Sheltered Tell us...
Hardiness: Hardy (H4) Tell us...

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