Acer pictum subsp. okamotoanum

RHS Plant Profile

Okamoto painted maple

Synonyms

Acer mono subsp. okamotoanum, Acer okomotoanum, Acer okamotoanum

Trees

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Vigorous, deciduous, wide-spreading tree, varying in height from 10-12m tall in cultivation, to about 20m in height in the wild, with pale brown to yellowish-grey bark. Mid-green leaves with triangular, taper-pointed 7-lobes, pale green beneath, and 12-15cm across, turn yellow in autumn. Yellow-green spring flowers are followed by yellow-green winged fruits in autumn

Position

Full sun, Partial shade

Soil Types

Clay, Sand, Loam

Max Height

8-12 metres

Max Spread

4-8 metres

Size

Time to Maturity: 10–20 years
Max Spread: 4-8 metres
Max Height: 8-12 metres

Growing Conditions

Clay Sand Loam

Moisture: Moist but well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or North–facing or South–facing or West–facing
Exposure: Exposed or 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): H6

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Sapindaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Bushy, Spreading branched
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: Correct

How to Grow

Cultivation

Grow in fertile, moist but well-drained soil in sun or partial shade. See tree cultivation for further advice

Propagation

Propagate by seed (trees and shrubs), layering in autumn, grafting in late winter or softwood cuttings in early summer

Suggested planting locations and garden types

Cottage and informal garden
Wildlife gardens

Pruning

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

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