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Herbaceous Perennial

Polemonium 'Sapphire'

Jacob's ladder 'Sapphire'

A bushy, clump-forming perennial to around 45cm high, forming a low mound of long, pinnate leaves, divided into 10-20 elliptic leaflets held in offset pairs. Arching sprays of nodding blue flowers are produced in late spring

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Ultimate height

0.1–0.5 metres

Time to ultimate height

2–5 years

Ultimate spread

0.1–0.5 metres

Chalk

Clay

Loam

Moisture

Moist but well–drained

pH

Acid, Alkaline, Neutral

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Full sun
Partial shade

Aspect

East–facing or South–facing or West–facing

Exposure

Exposed or Sheltered

Hardiness
Hardiness ratings
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
H1a: under glass all year (>15C)
H1b: can be grown outside in the summer (10 - 15)
H1c: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20)

Botanical details

Family: Polemoniaceae
Native to GB / Ireland: No
Foliage: Deciduous
Habit: Bushy, Clump forming
Genus: Polemonium can be annuals or herbaceous perennials or upright or spreading habit, with pinnate leaves and usually clustered, tubular, bell, or funnel-shaped flowers
Name status: Accepted

How to grow

Cultivation

Grow in fertile, moist but well-drained soil, will benefit from some shade where summers are hot

Propagation

Propagate by division in spring

Suggested planting locations and garden types

Cottage and informal garden
Patio and container plants
Flower borders and beds

Pruning

Deadhead regularly to encourage new flowers

Pests

Generally pest-free

Diseases

May be susceptible to powdery mildews

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