• AGM plants

    AGM plants have been through a rigorous trial and assessment programme. They are:

    • Excellent for ordinary use in appropriate conditions
    • Available to buy
    • Of good constitution
    • Essentially stable in form & colour
    • Reasonably resistant to pests & diseases

Campanula trachelium

nettle-leaved bellflower

nettle-leaved bellflower

© RHS 1999

  • Other common names nettle-leaved bellflower
    blue devil bellflower

    blue devils
    blue foxglove
    Coventry bellflower
    cover-keys
    gloves of Mary
    great throatwort
    great throat root
    throatwort

    see more
  • Family Campanulaceae

  • Genus Campanula may be annuals, herbaceous or evergreen perennials, with bell or star-shaped, often blue, flowers in late spring or summer

  • Details C. trachelium is a robust perennial with nettle-like, deeply toothed leaves and erect, leafy stems bearing a raceme of bell-shaped lavender-blue flowers 3cm long in summer

  • Plant range Eur., N Afr. & Sib.

Characteristics

  • Foliage Deciduous

  • Habit Bushy

  • 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

Sunlight

  • Full Sun

  • Partial Shade

  • Aspect South-facing or North-facing or West-facing or East-facing

  • Exposure Exposed or Sheltered

Soil

  • Sand

    Sand

  • Clay

    Clay

  • Chalk

    Chalk

  • Loam

    Loam

  • MoistureWell-drained, Moist but well-drained

  • SoilSand, Clay, Chalk, Loam

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 0.5-1 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Any fertile, well-drained soil in sun or part shade. The flower colour is best in shade

Propagation Propagate by seed in containers in a cold frame in spring. Divide in spring or autumn. Take stem-tip cuttings from new growth after flowering

Suggested planting locations and garden types Flower borders and beds Underplanting of Roses and Shrubs Cottage & Informal Garden Wildflower meadow

How to care

Pruning Cut back after flowering to prevent seeding and to encourage a second flush of flower

Pests Vulnerable to slugs and snails

Diseases Powdery mildew and rust may be problematic

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