Acer rubrum Summer Red ('Hosr')

RHS Plant Profile

red maple [Summer Red]

Synonyms

Acer rubrum 'Hosr'

Trees

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An oval-headed then broadly pyramidal, deciduous tree about 15m tall, the 3-5 lobed palmate, dark green leaves to 10cm long, the new summer growth is reddish as well as the young spring leaves, then turning yellow, orange and red in autumn. Upright clusters of tiny red flowers are borne in spring followed by dark red winged fruits in autumn

Position

Full sun, Partial shade

Soil Types

Clay, Sand, Loam

Max Height

Higher than 12 metres

Max Spread

wider than 8 metres

Size

Time to Maturity: 10–20 years
Max Spread: wider than 8 metres
Max Height: Higher than 12 metres

Growing Conditions

Clay Sand Loam

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

Position

Full sun Partial shade

Aspect: East–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
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: Trade

How to Grow

Cultivation

Grow in fertile, moist but well-drained soil in sun or partial shade. Fairly lime-tolerant but best grown in acid soil for best leaf colour. 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 Grow in fertile, moist but well-drained soil in sun or partial shade. See tree cultivation for further advice

Suggested planting locations and garden types

Architectural
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