Clethra alnifolia 'Hummingbird'

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white alder 'Hummingbird'

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white alder 'Hummingbird' RHS
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'Hummingbird' is a compact shrub, up to 1.2m high, with glossy dark green leaves which turn yellow in autumn. Many feathery spikes of sweetly clove-scented white flowers appear in mid- to late summer

Position

Partial shade

Soil Types

Loam, Sand

Max Height

1-1.5 metres

Max Spread

1-1.5 metres

Size

Time to Maturity
5–10 years
Max Spread
1-1.5 metres
Max Height
1-1.5 metres

Growing Conditions

Loam Sand
Moisture
Moist but well–drained
pH
Acid

Position

Partial shade
Aspect
North–facing or West–facing or South–facing or East–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

Fragrance Flower
Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Clethraceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Suckering
Genus
Clethra can be deciduous or evergreen trees or shrubs, sometimes with attractive bark, with simple leaves and small, fragrant, usually white, bell-shaped flowers in racemes or panicles
Name Status
Accepted

How to Grow

Cultivation

Grow in humus-rich, moist, well-drained, lime-free soil in dappled shade, in the shelter of an open woodland garden or a lightly-shaded shrub border; after pruning, mulch with well-rotted leaf mould

Propagation

Propagate by division of suckers, by heeled semi-ripe cuttings of lateral shoots in summer, or by layering in late autumn or early spring

Suggested planting locations and garden types

  • Cottage and informal garden
  • Low Maintenance

Pruning

Pruning group 1; in winter, remove some of the older stems, leaving the strongest suckers; cut off old flowerheads in spring

Pests

Generally pest-free

Diseases

Generally disease-free