• 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

Astilbe glaberrima var. saxatilis

Smooth rock astilbe

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
Smooth rock astilbe

© � RHS 2002

  • Other common names Smooth rock astilbe

  • Synonyms Astilbe glaberrima minor saxosa
    Astilbe glaberrima saxosa

    Astilbe glaberrima � 'Saxosa'
    Astilbe japonica 'Saxosa'
    Astilbe 'Saxosa'

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  • Genus Astilbe are rhizomatous herbaceous perennials with attractive, usually ternately divided leaves and erect plume-like panicles of tiny white, pink or purple flowers in summer. The old, brown flower-heads remain attractive in autumn

  • Family Saxifragaceae / Saxifragaceae

  • Species A. glaberrima var. saxatilis is a dwarf herbaceous perennial to 15cm, with glossy bronze-green, deeply divided leaves and short sprays of pink-tinged white flowers

  • Plant range Japan

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 West-facing or East-facing

  • Exposure Exposed or Sheltered

Soil

  • Chalk

    Loam

  • MoisturePoorly-drained, Moist but well-drained

  • SoilLoam

  • pHNeutral, Acid, Alkaline

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 moist, fertile, humus-rich soil in full sun or grow in partial shade where soil is likely to dry out in the summer. Plants must be divided every three to four years to maintain vigour.

Propagation Propagate by division in late winter or early spring, pot divisions under glass and plant out in late spring.

Suggested planting locations and garden types Flower borders and beds Cottage & Informal Garden Rock Garden

How to care

Pruning Cut back after flowering

Pests Generally pest free

Diseases Powdery mildews may be troublesome

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