Magnolia kobus

RHS Plant Profile

northern Japanese magnolia

Synonyms

Magnolia kobus var. borealis
Magnolia praecocissima

Trees

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A broadly conical, deciduous tree to 10m tall, with mid-green leaves to 15cm long, and fragrant, goblet to saucer-shaped, white flowers to 10cm wide, in mid-spring, followed by pink fruits splitting to reveal scarlet seeds

Position

Full sun, Partial shade

Soil Types

Clay, Loam, Sand

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 Loam Sand

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

Position

Full sun Partial shade

Aspect: West–facing or East–facing or South–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): H6

Colour & Scent

Fragrance Flower

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Magnoliaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Bushy
Genus: Magnolia can be deciduous or evergreen trees or shrubs, with large, showy, often fragrant flowers, often opening before the leaves, and sometimes followed by colourful cone-like fruit
Name Status: Correct
Plant Range: Japan, Korea

How to Grow

Cultivation

Grow in moist but well-drained neutral to acid soil in full sun or part shade with shelter from cold winds. Late frosts may damage flower buds. See magnolia cultivation

Propagation

Propagate by seed in autumn and spring, softwood cuttings from late spring to early summer or semi-ripe cuttings in late summer or autumn

Suggested planting locations and garden types

Architectural
Cottage and informal garden

Pruning

Minimal pruning required, see magnolia pruning. Deciduous magnolias should only be pruned between midsummer and early autumn

Pests

May be susceptible to scale insects, horse chestnut scale and capsid bug

Diseases

May be susceptible to coral spot, phytophthora, grey moulds, honey fungus, a virus or fungal leaf spot