College of Agriculture, Health and Natural Resources

Plant Database

Clethra barbinervis

Japanese Clethra

Clethraceae

Japanese ClethraJapanese ClethraJapanese ClethraJapanese ClethraJapanese ClethraJapanese ClethraJapanese ClethraJapanese ClethraJapanese Clethra
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Habitat

  • native to Japan
  • hardy to zone 5

Habit and Form

  • a deciduous large shrub or small tree
  • 10' to 20' tall
  • rounded habit
  • medium texture
  • fast growth rate

Summer Foliage

  • alternate leaf arrangement
  • deciduous, simple leaves
  • ovate leaf shape
  • 2" to 5" long
  • serrated leaf margin
  • dark green leaf color

Autumn Foliage

  • bronze to red fall color

Flowers

  • numerous, small white flowers held in racemes.
  • racemes are 4" to 6" long
  • found at terminal tips
  • nicely fragrant
  • blooms in July and August
  • blooms on current seasons growth
  • showy

Fruit

  • small capsules
  • borne in long terminal spikes
  • turn brown in fall

Bark

  • smooth exfoliating bark
  • gray to reddish brown color

Culture

  • prefers moist, fertile soil
  • transplant from container or B&B
  • may be slow to establish and some twig tip dieback may occur during the first winter.
  • relatively easy to grow
  • full sun to partial shade
  • avoid hot, dry sites

Landscape Use

  • screen
  • specimen perhaps
  • in groupings
  • shrub border
  • colonizing nature can be useful
  • highly useful for late summer fragrant flowers
  • site the plant so fragrance can be appreciated
  • tolerant of ocean-side plantings
  • naturalistic/native landscapes

Liabilities

  • relatively pest free except for spider mites
  • spider mites can be severe on plants in hot, dry locations
  • hard to find

ID Features

  • fragrant spires of white flowers in mid to late summer
  • persistent fruit capsules
  • ovate, alternate, deciduous leaves with serrations
  • suckering, colonial type growth
  • exfoliating bark

Propagation

  • by seed
  • easily rooted by summer cuttings

Cultivars/Varieties

  • none

© Copyright Mark H. Brand, 1997-2015.

The digital materials (images and text) available from the UConn Plant Database are protected by copyright. Public use via the Internet for non-profit and educational purposes is permitted. Use of the materials for profit is prohibited.

Citation and Acknowledgements: University of Connecticut Plant Database, https://plantdatabase.uconn.edu/, Mark H. Brand, Department of Plant Science and Landscape Architecture, Storrs, CT 06269-4067 USA.