• 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

Erigeron 'Dunkelste Aller'

fleabane 'Dunkelste Aller'

fleabane 'Dunkelste Aller'

© RHS

  • Other common names fleabane 'Dunkelste Aller'

  • Synonyms Erigeron DARKEST OF ALL
    Erigeron 'Darkest of All'

  • Family Asteraceae

  • Genus Erigeron can be annuals, biennials or perennials with simple or lobed leaves, and daisy-like flowers with many slender rays, appearing over a long period in summer

  • Details 'Dunkelste Aller' is an herbaceous perennial forming a clump of erect stems to 60cm, bearing oval grey-green leaves and clusters of yellow-centred, semi-double, deep violet daisy-like flower-heads

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)

    H6

Colour

Sunlight

  • Full Sun

  • Aspect South-facing or West-facing

  • Exposure Exposed or Sheltered

Soil

  • Loam

    Loam

  • Chalk

    Chalk

  • Sand

    Sand

  • MoistureMoist but well-drained

  • SoilLoam, Chalk, Sand

  • 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 Grow in fertile, well-drained soil that remains moist in summer. Especially good for planting near the sea. Good drainage is needed, so growing in a raised bed can be useful

Propagation Cultivars are usually propagated by division or from basal softwood cuttings in spring

Suggested planting locations and garden types Flower borders and beds City & Courtyard Gardens Coastal Cottage & Informal Garden

How to care

Pruning Cut back at the end of the season

Pests Usually trouble free

Diseases Powdery mildew may be a problem

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