• 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

Symphytum officinale

common comfrey

common comfrey

© RHS

  • Other common names common comfrey
    alum

    backwort
    black root
    blackwort
    Bohemian comfrey
    bone-set
    bruisewort
    comfrey consound
    gum plant
    healing herb
    knit-back

    see more
  • Family Boraginaceae

  • Genus Symphytum are rhizomatous herbaceous perennials, sometimes invasive, with large leaves and nodding clusters of tubular flowers

  • Details S. officinale is a robust, rather invasive perennial forming a clump of erect stems bearing elliptic leaves to 25cm in length, and terminal clusters of nodding, tubular bell-shaped, purple, pink or cream flowers 2cm in length in late spring and summer

  • Plant range Europe & temperate Asia

Characteristics

  • Foliage Deciduous

  • Habit Spreading / Branched

  • Toxicity Ingestion may cause severe discomfort

  • 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

  • Chalk

    Chalk

  • Clay

    Clay

  • Sand

    Sand

  • Loam

    Loam

  • MoistureMoist but well-drained, Poorly-drained

  • SoilChalk, Clay, Sand, Loam

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 1-1.5 metres

  • Ultimate spread 1-1.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Grow in moderately fertile, moist soil in sun or partial shade. Makes good groundcover but can become invasive, so site with care

Propagation Propagate by division of fleshy roots in spring. Propagate by root cuttings in early winter. Propagate by seed sown in pots in a cold frame in autumn or spring

Suggested planting locations and garden types Low Maintenance Underplanting of Roses and Shrubs Wildflower meadow Wildlife Gardens

How to care

Pruning Cut back after flowering to encourage neat, young foliage

Pests Generally pest free

Diseases Generally disease free

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