• 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

Symphyotrichum cordifolium 'Sweet Lavender'

blue wood 'Sweet Lavender'

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
blue wood 'Sweet Lavender'

© RHS

  • Other common names blue wood 'Sweet Lavender'

  • Synonyms Aster cordifolius 'Sweet Lavender'

  • Family Asteraceae

  • Genus Symphyotrichum includes around 90 species of annuals, biennials and perennials, mostly spread through the Americas, that were formerly included within the genus Aster. Leaves are simple, lance-shaped and entire, but it is their daisy-like flowerheads that they are grown for; central disc florets are typically yellow, surrounded by strap-shaped ray florets in shades of pink, blue, purple or white

  • Details 'Sweet Lavender' is an herbaceous perennial to 1.2m, with dark green leaves and open, arching sprays of small, lavender-blue flowers 2cm wide in autumn

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 West-facing or East-facing

  • Exposure Exposed or Sheltered

Soil

  • Sand

    Sand

  • Clay

    Clay

  • Chalk

    Chalk

  • Loam

    Loam

  • MoistureMoist but well-drained

  • SoilSand, Clay, Chalk, Loam

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 1-1.5 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Grow in well-cultivated, fertile, moist soil in sun or partial shade; may need staking

Propagation Propagate by division in spring; division every third year to maintain vigour

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

How to care

Pruning Cut back in late autumn

Pests Generally pest free

Diseases Asters may suffer Verticillium wilt, powdery mildews and grey moulds

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