• 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

Astrantia major

greater masterwort

greater masterwort

© RHS

  • Other common names greater masterwort
    astrantia

    great black masterwort
    melancholy gentleman
    black hellebore

    see more
  • Synonyms Astrantia biebersteinii
    Astrantia carniolica major

  • Family Apiaceae

  • Genus Astrantia are clump-forming herbaceous perennials with palmately lobed basal leaves and branched, erect, wiry stems bearing compact umbels of tiny flowers surrounded by a rosette of showy bracts

  • Details A. major is an erect, clump-forming perennial with scarcely 3-5-lobed leaves, and flower stems to 60cm, bearing flower heads in stalked, compound umbels. Clusters of tiny, whitish-green flowers are surrounded by petal-like bracteoles which are whitish, tinged with green and pink, with conspicuous veining. Several subspecies of this plant have contributed to the many garden selections

  • Plant range C & E Europe

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 East-facing or West-facing

  • Exposure Sheltered or Exposed

Soil

  • Loam

    Loam

  • Clay

    Clay

  • MoistureMoist but well-drained, Well-drained

  • SoilLoam, Clay

  • 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 Best grown in moist, fertile, preferably humus-rich soil in sun or part shade; drier conditions tolerated

Propagation Propagate by seed in containers in a cold frame as soon as ripe or propagate by division in spring

Suggested planting locations and garden types Underplanting of Roses and Shrubs Flower borders and beds City & Courtyard Gardens Cottage & Informal Garden

How to care

Pruning Cut back after flowers have faded to tidy and encourage a fresh flush of leaf growth

Pests May be affected by slugs and aphids

Diseases Powdery mildews may be troublesome

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