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Tree Clethra Clethra barbinervis

Other Common Name(s):

Phonetic Spelling
KLETH-rah bar-BIN-ner-viss
Description

Japanese clethra is a dense, deciduous, oval-shaped flowering shrub maturing to 9 feet high by 9 feet wide, although specimens do reach heights of 20 feet. In its native Japan, it is typically found in wooded hills and mountains, in sunny deciduous forests on mountains, or in stony and dry places at elevations of 3200 to 5000 feet.This plant prefers partial shade as well as moist, lime free, organically rich, acidic, and well-drained soil. It will tolerate a sunny site and is generally hardy, although it can suffer from harsh winter winds in Zone 5 where it may not be reliably winter hardy throughout. Summer cuttings can be easily rooted and it will spread through suckering to form colonies.

Japanese Clethra produces dropping, fragrant white flowers on the current season's growth in summer into early fall and glossy, dark green leaves which turn bright yellow (sometimes red) in autumn for good fall color. Dark brown seed capsules persist into winter and the polished, grayish-brown bark exfoliates. Flower spikes are more horizontal and drooping and less fragrant than those of Clethra alnifolia (Summersweet). Japanese Clethra is trouble-free shrub useful in small grouping in conspicuous locations where its summer bloom, good fall color, bark and seed spikes) can be viewed.

The genus Clethra comes from the Greek klethra  for alder, which this plant's leaves resemble. The species barbinervis means with veins barbed or bearded.

Diseases, Insect Pests, and Other Plant Problems:

No known diseases or insect pests. Spider mites can be a problem in hot, dry sites. Spring growth can be damaged by a late frost and may need protection.

See this plant in the following landscape:
Cultivars / Varieties:
  • 'Dwarf'
  • 'Takeda Nishiki'
    Variegated leaves of pink, green and white in spring; also known as 'First Snow'.
'Dwarf', 'Takeda Nishiki'
Tags:
#fragrant#deciduous#interesting bark#white flowers#shrub#winter interest#fall interest#summer flowers#bronze leaves#maroon leaves#symphony#rounded#pollinator plant#fall color red#partial shade tolerant#bee friendly
 
Cultivars / Varieties:
  • 'Dwarf'
  • 'Takeda Nishiki'
    Variegated leaves of pink, green and white in spring; also known as 'First Snow'.
'Dwarf', 'Takeda Nishiki'
Tags:
#fragrant#deciduous#interesting bark#white flowers#shrub#winter interest#fall interest#summer flowers#bronze leaves#maroon leaves#symphony#rounded#pollinator plant#fall color red#partial shade tolerant#bee friendly
  • Attributes:
    Genus:
    Clethra
    Species:
    barbinervis
    Family:
    Clethraceae
    Life Cycle:
    Woody
    Recommended Propagation Strategy:
    Seed
    Stem Cutting
    Country Or Region Of Origin:
    East Asia, China to Japan
    Wildlife Value:
    Flowers are very attractive to butterflies and bees.
    Dimensions:
    Height: 10 ft. 0 in. - 20 ft. 0 in.
    Width: 10 ft. 0 in. - 15 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Shrub
    Woody Plant Leaf Characteristics:
    Deciduous
    Habit/Form:
    Dense
    Erect
    Oval
    Rounded
    Growth Rate:
    Rapid
    Maintenance:
    Medium
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Dappled Sunlight (Shade through upper canopy all day)
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    High Organic Matter
    Loam (Silt)
    Soil pH:
    Acid (<6.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Moist
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    4b, 4a, 5a, 5b, 6b, 6a, 7b, 7a, 8a, 8b
  • Fruit:
    Fruit Color:
    Brown/Copper
    Display/Harvest Time:
    Fall
    Fruit Type:
    Capsule
    Fruit Description:
    Flowers give way to dark brown seed capsules which persist into winter.
  • Flowers:
    Flower Color:
    White
    Flower Inflorescence:
    Raceme
    Flower Value To Gardener:
    Fragrant
    Showy
    Flower Bloom Time:
    Fall
    Summer
    Flower Size:
    1-3 inches
    Flower Description:
    Flowers from July into late August. Horizontally drooping, terminal racemes (4 to 6 inches long) hold numerous, pleasantly fragrant flowers.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Gold/Yellow
    Green
    Leaf Feel:
    Glossy
    Leaf Value To Gardener:
    Showy
    Deciduous Leaf Fall Color:
    Brown/Copper
    Red/Burgundy
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Ovate
    Leaf Margin:
    Serrate
    Hairs Present:
    No
    Leaf Length:
    3-6 inches
    Leaf Description:
    This plant has simple, sharply serrated, lustrous, and dark green leaves which are 2 to 5 inches long and tend to be clustered at ends of branches. The leaves are bronze-red to maroon in the fall.
  • Bark:
    Bark Color:
    Dark Brown
    Light Brown
    Red/Burgundy
    Surface/Attachment:
    Peeling
    Smooth
    Bark Description:
    Smooth, polished brown to cinnamon bark that exfoliates.
  • Stem:
    Stem Is Aromatic:
    No
  • Landscape:
    Landscape Location:
    Woodland
    Landscape Theme:
    Butterfly Garden
    Pollinator Garden
    Shade Garden
    Winter Garden
    Design Feature:
    Barrier
    Flowering Tree
    Hedge
    Screen/Privacy
    Attracts:
    Bees
    Butterflies
    Resistance To Challenges:
    Salt