Woody > Clethra > Clethra barbinervis > Clethra barbinervis
Clethra barbinervis
Japanese Clethra
Origin: Native from Eastern China to Japan.
Mike's
Opinion
"
Clethra Barbinervis is mainly tropical and found in Eastern Asia and Japan. It is known for its many attractive features. The barks texture is smooth but flaky with various colors including slate grey, lavender, and cinnamon. Can be multi-stemmed if not pruned regularly, is suggested that you do maintain pruning the shrub to approve attractiveness of the bark. Leaves become incredibly unique in the autumn season when the color changes to an orange/red bronze. This shrub blooms in the mid-summer releasing a pleasant fragrance from numerous white bell flowers that form straight from the drooping panicles. These shrubs are slow growing and extremely low maintenance as well as pest-free, which make them a great use in landscaping.
Michael Pascoe, NDP., ODH., CLT., MSc. (Plant Conservation)
"
| Family |
| Clethraceae |
| Genus |
| Clethra |
| Species |
| barbinervis |
| Category |
| Woody |
| Type |
| Shrub (deciduous) |
| USDA Hardiness Zone |
| 4 - 8 |
| Canadian Hardiness Zone |
| 5 - 8 |
| RHS Hardiness Zone |
| H4 |
| Temperature (°C) |
| (-20) |
| Temperature (°F) |
| (-4) |
| Height |
| 3 - 7 |
| Spread |
| 3 - 7 |
Photographs
Cultivars
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Description and Growing Information
Flowering Period
| General Description |
| Slow growing, large deciduous shrub with drooping panicles, that bloom fragrant white bell flowers. Extremely attractive to pollinators from mid to late summer when in full bloom. Known for it’s remarkable bark features such as a smooth and flaky texture as well as it’s various colors. |
| Landscape |
| This large shrub can also be interpreted as a small tree, is commonly used as an addition to woodland garden. The exfoliating bark features make this shrub an attractive winter addition. It can be planted as a specimen plant or in smaller groupings, as it is known as a pest free shrub. |
| Cultivation |
| Clethra Barbinervis was introduced into cultivation in 1870. It is a low maintenance shrub and prefers full sun to part shade, as well as medium to wet well-drained soils. This shrub can tolerate slightly acidic soil. Clethras thrive in rich woodland soils and prefer consistent moisture. Protection is important during the winter season as the winds and cold temperatures could potentially harm the shrub. |
| Shape |
| If left unpruned it will grow as a multi-stemmed shrub or small tree |
| Growth |
| Medium |
| ID Characteristic |
| Simple glossy, dark green leaves with serrated indentations. Dramatic white bell flowers quite like the lily of the valley flowers. Exfoliating polished bark with distinguishing colours. Incredibly attractive red/orange colour in the Autumn season. |
| Pests |
| Commonly known to be a trouble-free shrub except for spider mites. Spider mites can be hard to find but can be severe in hot and dry conditions. |
| Habitat |
| Mostly seen in Woodland locations along stream banks and ponds as it needs consistent moisture. This plant is mainly hardy but can fail when temperatures drop below -20?. |
| Bark/Stem Description |
| Incredibly attractive rich multi-colored bark that peels off to show tones of grey, lavender, and cinnamon. These colors make the bark attractive and noticeable in the winter months. Branches grow upward but have a dropping like appearance that look like Dogwood branches. |
| Flower/Leaf Bud Description |
| Found at the terminal tips of the branches the horizontal drooping panicles are 4-6 inches in length and bloom into white flowers. |
| Leaf Description |
| The species name Barbinervis refers to the veins of the leaves that appear to be “hairy”. The young leaves are known to be edible. The shape of the leaves is described as broadly obovate with tooth margins and a drawn-out tip. The leaves are assembled in an alternative arrangement and gather at the bottom of the shoots. The top of the leaf is a dark green color as the bottom is more of a light green color if the soil is not to acidic. |
| Flower Description |
| Flowers bloom in mid-summer from July-August. The flowers bloom from the drooping panicles into numerous small white bell flowers. These flowers give off a fragrance that attract many pollinators such as bees and butterflies. The shrub must be pruned immediately after flowering. |
| Fruit Description |
| The fruit is a 3-valved capsule with a persistent calyx that contains many flatten seeds. In the fall months the fruit turns dark brown and persists into winter. |
| Colour Description |
| During the warmer season’s leaves are a glossy dark green, flowers are a pale white, and the bark shows shades of slate grey, lavender, and cinnamon. In the Autumn season leaves turn an orange to red bronze, flowers are no longer in bloom, and the bark remains the same shades of slate grey, lavender, and cinnamon. The fruit is found on the shrub during the Autumn and Winter months and remains a dark brown color throughout. |
| Texture Description |
| The slow growing deciduous shrub grows tall and is a medium textured plant. This texture remains the same throughout all seasons. |
| Notable Specimens |
| Missouri Botanical Garden, St. Louis, Missouri |
| Propagation |
| To propagate you must start by sowing the seed in the early spring in a greenhouse. Must be kept moist and covered. Germination will occur within the first 3 months when kept at 13?C minimum. These seedlings must be kept in a greenhouse for the first winter to ensure proper growth and avoid death of the seedling. Planting can take place when the plant is 20cm in height and must be planted in the late spring to early summer after the last frost. Can also be propagated through soft wood cuttings. Root cuttings of suckers can be completed when the shrub is dormant in the months of December and January. |
| Ethnobotanical Uses (Disclaimer) |
| Today, this shrub is often used in landscaping for accent plants and small groupings, often found in moist soils such as stream banks and alongside ponds. Most of these shrubs are tropical and come from the Western Hemisphere. Some features of this shrub are that the young leaves are edible, and the bark is used for making charcoal and utensils. |
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