• 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

Thalictrum delavayi 'Hewitt's Double' (d)

Chinese meadow rue 'Hewitt's Double'

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
Chinese meadow rue 'Hewitt's Double'

© � RHS

  • Other common names Chinese meadow rue 'Hewitt's Double'

  • Synonyms Thalictrum dipterocarpum 'Hewitt's Double' misapplied

  • Genus Thalictrum can be rhizomatous or tuberous perennials with ternately or pinnately divided, often attractive foliage, and panicles or racemes of small flowers with showy stamens and sometimes large colourful petal-like sepals

  • Family Ranunculaceae / Ranunculaceae

  • Species 'Hewitt's Double' is an erect herbaceous perennial to 1.5m in height, with attractively divided leaves and tall panicles of long-lasting, rosette-like, double lilac-purple flowers

Characteristics

  • Foliage Deciduous

  • Habit Columnar_Upright#Columnar/Upright

  • Toxicity Contact with foliage may irritate the skin

  • 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

    H7

Colour

Sunlight

  • Partial Shade

  • Aspect East-facing or West-facing

  • Exposure Sheltered

Soil

  • Chalk

    Clay

  • Chalk

    Loam

  • Chalk

    Chalk

  • MoistureMoist but well-drained, Poorly-drained

  • SoilClay, Loam, Chalk

  • 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 moist, humus-rich soil in partial shade. May need staking

Propagation Propagate by division as new growth begins in the spring

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

How to care

Pruning Cut down stems once flowering is over

Pests Generally pest free

Diseases May be subject to powdery mildews in dry conditions

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