• 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

Acer palmatum 'Nigrum' (A)

black Japanese maple

black Japanese maple

© RHS

  • Other common names black Japanese maple

  • Family Sapindaceae

  • Genus Acer can be deciduous trees or large shrubs with paired, often palmately-lobed leaves and small flowers followed by characteristic winged fruits. Many have fine autumn colour, and some have ornamental stems

  • Details 'Nigrum' is a deciduous shrub or small tree with 5- to 7-lobed leaves, deep purple in spring and summer, becoming crimson 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)

    H6

Colour

Sunlight

  • Full Sun

  • Partial Shade

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

  • Exposure Sheltered

Soil

  • Chalk

    Sand

  • Chalk

    Clay

  • Chalk

    Chalk

  • Chalk

    Loam

  • MoistureMoist but well-drained

  • SoilSand, Clay, Chalk, Loam

  • pHAcid, Neutral

Size

  • Ultimate height 2.5-4 metres

  • Ultimate spread 1.5-2.5 metres

  • Time to ultimate height 20-50 years

How to grow

Cultivation Grow in a moist but well-drained soil. Water in summer if necessary. Leaf colour is best in partial shade, although full sun can be tolerated. Leaf scorch can be caused by lack of soil moisture or excessive exposure

Propagation Propagate by grafting or softwood cuttings

Suggested planting locations and garden types Low Maintenance City & Courtyard Gardens Cottage & Informal Garden

How to care

Pruning Pruning group 1

Pests Aphids and horse chestnut scale may be a problem

Diseases Verticillium wilt sometimes a problem

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