Polemonium 'Blue Pearl'

RHS Plant Profile

Jacob's ladder 'Blue Pearl'

RHS

Synonyms

Polemonium pulcherimum 'Blue Pearl'

Herbaceous Perennial

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A compact herbaceous perennial up to 30cm high with fresh green pinnate leaves and sky-blue flowers in early summer

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 0.1-0.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: South–facing or North–facing or West–facing or East–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): H7

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Polemoniaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Matforming
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: Unresolved

How to Grow

Cultivation

Grow in any fertile, leafy, moist but well-drained soil in full sun or partial shade

Propagation

Propagate by division

Suggested planting locations and garden types

Rock garden
City and courtyard gardens
Cottage and informal garden
Flower borders and beds

Pruning

No pruning required

Pests

Generally pest-free

Diseases

Generally disease-free but may be susceptible to powdery mildews