Polemonium caeruleum

RHS Plant Profile
Jacob's ladder

Other common names

American great valerian, charity, Greek valerian, ladder to heaven, make-bate

Synonyms

Polemonium pulchellum Turcz.

Plants for pollinators
Herbaceous Perennial

A clump-forming perennial to 90cm tall, with ladder-like, pinnate mid-green leaves composed of leaflets, and stiff stems bearing sprays of blue flowers 2.5cm wide with prominent yellow stamens in early summer; often seeds about rather freely

Position

Full sun, Partial shade

Soil Types

Clay, Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity
2–5 years
Max Spread
0.1-0.5 metres
Max Height
0.5-1 metres

Growing Conditions

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
H7

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Polemoniaceae
Native to GB/Ireland
Yes
Foliage
Deciduous
Habit
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
Correct
Plant Range
Temperate Eurasia

How to Grow

Cultivation

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

Propagation

Propagate by seed sown in containers, in a cold frame in autumn or spring, or divide in spring

Suggested planting locations and garden types

  • Coastal
  • Wildlife gardens
  • Wildflower meadow
  • City and courtyard gardens
  • Cottage and informal garden
  • Flower borders and beds

Pruning

No pruning required. Cut back foliage to ground level at the end of the season

Pests

Generally pest-free

Diseases

Powdery mildews can sometimes be a problem