• 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

Cosmos bipinnatus 'Gazebo White'

cosmea 'Gazebo White'

© RHS
  • Other common names cosmea 'Gazebo White'

  • Family Asteraceae

  • Genus Cosmos can be annuals or perennials with simple or pinnately divided leaves and large, long-stalked daisy-like flowers in summer

  • Details 'Gazebo White' is a bushy, relatively compact half-hardy annual, to around 70cm tall, with finely-divided, green leaves. Large, white flowers, are borne throughout the summer and into early autumn, on erect, well-branched stems

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)

    H3

Colour

Sunlight

  • Full Sun

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

  • Exposure Sheltered

Soil

  • Loam

    Loam

  • Sand

    Sand

  • Chalk

    Chalk

  • Clay

    Clay

  • MoistureMoist but well-drained

  • SoilLoam, Sand, Chalk, Clay

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 0.5-1 metres

  • Ultimate spread 0.5-1 metres

  • Time to ultimate height 1 year

How to grow

Cultivation Grow in moist, but well-drained soil in full sun. Suited to annual or cut-flower borders or as a summer infill

Propagation Propagate by seed sown at 16°C in mid-spring under glass, or in situ in late spring

Suggested planting locations and garden types Cut Flowers Flower borders and beds Cottage & Informal Garden Patio & Container Plants

How to care

Pruning Deadhead to prolong the flowering season

Pests Aphids and slugs may be troublesome

Diseases May be susceptible to grey moulds

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