• 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

Cephalaria gigantea

giant scabious

giant scabious

© RHS 1998

  • Other common names giant scabious
    yellow scabious

  • Synonyms Cephalaria caucasica
    Cephalaria tatarica hort.

    Scabiosa gigantea
    Scabiosa tatarica

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  • Family Caprifoliaceae

  • Genus Cephalaria are annuals or perennials with pinnately divided leaves and scabious-like flower-heads

  • Details C. gigantea is a perennial forming a clump of pinnately lobed basal leaves, with tall, branched stems carrying light yellow flower-heads to 6cm across in summer

  • Plant range Caucasus, Siberia

Characteristics

  • Foliage Deciduous

  • Habit Columnar/Upright

  • 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 East-facing or West-facing or North-facing

  • Exposure Exposed or Sheltered

Soil

  • Chalk

    Loam

  • Chalk

    Chalk

  • Chalk

    Sand

  • Chalk

    Clay

  • MoistureMoist but well-drained

  • SoilLoam, Chalk, Sand, Clay

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 1.5-2.5 metres

  • Ultimate spread 0.5-1 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Grow in a fertile moist but well-drained soil in sun or partial shade. Needs staking in exposed gardens.

Propagation Propagate by seed sown in pots in a cold frame in early spring or propagate by division in spring

Suggested planting locations and garden types Flower borders and beds Cut Flowers Wildlife Gardens

How to care

Pruning Cut back after flowering

Pests Generally pest free

Diseases Generally disease free

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