Alphabetical Plant Listing

Clethra barbinervis (Japanese Clethra)

Japanese Clethra, Japanese Sweet Shrub, White Alder


Slow-growing, Clethra barbinervis (Japanese Clethra) is a large deciduous shrub or handsome small tree of upright-spreading habit boasting large, drooping panicles, 4-6 in. long (10-15 cm), of pleasantly fragrant white flowers. Blooming from mid to late summer, they nod forward and gently twist in graceful horizontal sprays, when few other shrubs or trees are in bloom. They are very attractive to bees, butterflies and other pollinators and give way to spikes of dark brown fruits which persist into winter, providing continuing interest. The serrated, glossy, dark green leaves, 2-6 in. long (5-15 cm), warm up to bright golden-yellow in fall, before falling to the ground, revealing the richly colored exfoliating bark. Equally remarkable, the bark is smooth, polished, exquisitely mottled cinnamon, salmon buff, and slate gray. A wonderful, trouble-free shrub with four seasons of interest that is perfect for moist, slightly acidic, well-drained soils. Excellent as a specimen plant or in small groupings.

  • Recipient of the prestigious Award of Garden Merit of the Royal Horticultural Society.
  • Grows up to 10-20 ft. tall (3-6 m) with a spread of 10-15 ft. (3-4.5 m).
  • A full sun to part shade lover, this plant is best grown in average, medium to wet, slightly acidic, well-drained soils. Full shade is tolerated.
  • Mass in mixed shrub borders for dramatic summer blooms. Great flowering shrub for shade or woodland gardens or along stream banks or ponds.
  • This plant enjoys an excellent resistance to pests and diseases.
  • Prune immediately after flowering. Propagate by seed or softwood cuttings.
  • Native from Eastern China to Japan.

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Requirements

Hardiness 5 – 8
Heat Zones 6 – 8
Climate Zones 5, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Shrubs, Trees
Plant Family Clethra
Exposure Full Sun, Partial Sun, Shade
Season of Interest Spring (Early,Mid,Late)
Summer (Early,Mid,Late)
Fall
Winter
Height 10' – 20' (3m – 6m)
Spread 10' – 15' (3m – 4.5m)
Spacing 120" – 180" (300cm – 450cm)
Water Needs Average
Maintenance Low
Soil Type Clay, Loam, Sand
Soil pH Acid
Soil Drainage Moist but Well-Drained
Characteristics Fragrant, Plant of Merit, Showy
Attracts Butterflies
Garden Uses Beds and Borders, Ponds and Streams
Garden Styles Informal and Cottage

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A.Bulano, Anna Gratys, backpacking, Shutterstock

While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.


Requirements

Hardiness 5 – 8
Heat Zones 6 – 8
Climate Zones 5, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Shrubs, Trees
Plant Family Clethra
Exposure Full Sun, Partial Sun, Shade
Season of Interest Spring (Early,Mid,Late)
Summer (Early,Mid,Late)
Fall
Winter
Height 10' – 20' (3m – 6m)
Spread 10' – 15' (3m – 4.5m)
Spacing 120" – 180" (300cm – 450cm)
Water Needs Average
Maintenance Low
Soil Type Clay, Loam, Sand
Soil pH Acid
Soil Drainage Moist but Well-Drained
Characteristics Fragrant, Plant of Merit, Showy
Attracts Butterflies
Garden Uses Beds and Borders, Ponds and Streams
Garden Styles Informal and Cottage

Great Plant Combination Ideas with Clethra

Guides with Clethra

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