Acer palmatum 'Emperor 1' (A)

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Japanese maple 'Emperor 1'

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Synonyms

Acer palmatum 'Wolff'
Acer palmatum Red Emperor

Shrubs Trees
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A large bushy deciduous shrub or small tree to 5m tall with 5-7-lobed, deep red-purple leaves, turning crimson in autumn. The leaves appear later than many other cultivars, reducing the risk of damage by spring frost

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

4-8 metres

Max Spread

4-8 metres

Size

Time to Maturity
20–50 years
Max Spread
4-8 metres
Max Height
4-8 metres

Growing Conditions

Chalk Clay Loam Sand
Moisture
Moist but well–drained
pH
Acid or Neutral

Position

Full sun Partial shade
Aspect
South–facing or East–facing or West–facing
Exposure
Sheltered
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)
H5

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Sapindaceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Columnar upright, Bushy
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
Name Status
Accepted
Horticultural Group

Horticultural Classification Codes

Horticultural Classification Codes are often given to genera which have a large number of species or cultivars. They are used to categorise cultivated plants based on specific, shared characteristics such as shape, colour, size or flowering time, and can be displayed as letters or numbers

For example:
Dahlia ‘Sunset Kate (Sin) = Single flower
Rosa ‘Marigold’ (HT) = Hybrid Tea

Acers in this amoenum group have large, palm-shaped leaves with finely-toothed edges

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. See Japanese maple cultivation

Propagation

Propagate by grafting, softwood cuttings or layering

Suggested planting locations and garden types

  • City and courtyard gardens
  • Cottage and informal garden
  • Architectural
  • Patio and container plants
  • Low Maintenance
  • Flower borders and beds

Pruning

Pruning group 1, pruning if necessary only from late autumn to midwinter

Pests

May be susceptible to Acer gall mite, aphids, caterpillars and horse chestnut scale

Diseases

May be susceptible to Verticillium wilt, Acer leaf scorch and honey fungus