• AGM plants

    AGM plants have been through a rigourous 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

Dodecatheon meadia f. album

White-flowered American cowslip

AGM plants

AGM plants have been through a rigourous 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
White-flowered American cowslip

© � RHS

  • Other common names White-flowered American cowslip

  • Synonyms Dodecatheon meadia 'Albiflorum'

  • Genus Dodecatheon are summer-dormant herbaceous perennials with basal rosettes of simple leaves and erect or arching stems bearing umbels of cyclamen-like flowers with strongly reflexed petals

  • Family Primulaceae / Primulaceae

  • Species D. meadia f. album is an herbaceous perennial to 45cm in height, with a rosette of lance-shaped leaves and erect stems bearing large umbels of white, nodding flowers 2cm in length

  • Plant range E North America

Characteristics

  • Foliage Deciduous

  • Habit Clump-forming

  • 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)
    Old hardiness ratings

    While we update our systems with the new hardiness ratings you may still see old hardiness ratings in your search results. These are denoted as 'Old'.

    • H1 - Requires heated glass
    • H2 - Requires unheated glass
    • H3 - Hardy outside in some regions of the UK
    • H4 - Hardy throughout the UK
    • H1 + H3 - Requires heated glass but may be grown outside in summer

    For full details of the hardiness ratings see

    see more

    H5

Colour

Sunlight

  • Full Sun

  • Partial Shade

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

  • Exposure Sheltered

Soil

  • Chalk

    Sand

  • Chalk

    Loam

  • Chalk

    Clay

  • MoistureMoist but well-drained

  • SoilSand, Loam, Clay

  • pHAcid, Neutral

Size

  • Ultimate height

    0.1-0.5 metres

  • Ultimate spread

    0.1-0.5 metres

  • Time to ultimate height

    2-5 years

How to grow

Cultivation Grow in a moist but well-drained, humus-rich soil in full sun or partial shade. Suitable for woodland or rock garden

Propagation Propagate by seed in pots in an open frame as soon as seed is ripe; seed needs exposure to cold before it will germinate or propagate by division in spring

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

How to care

Pruning No pruning required

Pests May be damaged by slugs and snails

Diseases Generally disease free

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