Hydrangea arborescens, commonly known as smooth hydrangea, wild hydrangea, or sevenbark, is a species of flowering plant in the family Hydrangeaceae. It is a small- to medium-sized, deciduous shrub up to 3 m (10 ft) tall that is native to the eastern United States.
The inflorescence of smooth hydrangea is a corymb. The showy, sterile flowers are usually absent or if present they are usually less than 1 cm in diameter. Flowering occurs May to July. Fruit is a ribbed brown capsule about 2 mm long; many are produced.
The leaves of smooth hydrangea are large (8 to 18 cm long), opposite, serrated, ovate, and deciduous. The lower leaf surface is glabrous or with inconspicuous fine hairs, appearing green; trichomes of the lower surface are restricted to the midrib and major veins.
At one time both ashy hydrangea (Hydrangea cinerea) and silverleaf hydrangea (Hydrangea radiata) were considered subspecies of smooth hydrangea. However, most taxonomists now consider them to be separate species.
Range and habitat
Smooth hydrangea is widely distributed across the eastern United States—from southern New York to the panhandle of Florida, west to eastern Oklahoma and southeastern Kansas. It is mainly found in moist soils under a hardwood forest canopy and is often common along woodland road banks and streams. It is common in the Delaware River Valley and in the Appalachian Mountains.
It is a host plant of the hydrangea sphinx moth.
This attractive native shrub is often cultivated for ornamental use. 'Annabelle' is the best known cultivar of this species; it is one of the most cold hardy of the hydrangeas. In the UK it has gained the Royal Horticultural Society's Award of Garden Merit. The cultivar 'Grandiflora' has flowers that resemble snowballs, similar to Viburnum plicatum.
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|Wikimedia Commons has media related to Hydrangea arborescens.|
- Cook, Will. Trees, shrubs, and woody vines of North Carolina. Wild Hydrangea (Hydrangea arborescens).
- Information on cultivar Annabelle
- Hydrangea arborescens Large-format diagnostic photos and information
- Hydrangea Thoughts I - Informative but non-scholarly essay on Hydrangea (Culture, History and Etymology).
- Briartech.com: Smooth Hydrangea, Hydrangea arborescens.