Clethra barbinervis • Summersweet

Clethra     • Summersweet  • リョウブ •   令法 •    ryōbu

We have only one clethra in the Garden, but it is a Japanese one:  it grows in Area F, along the second shortcut and under ginkgo and styrax trees.  The Plant List describes it as 10-12′ tall and having ‘fragrant blooms in July’.  It was only May 26 that I took the photos below, with buds already on:  like many other plants this year,  the clethra may bloom much sooner, due to unusually warm last winter. I will post a pic of full bloom later.


SJG • 5/26/15 – Clethra barbinervis • Summersweet in Area F, on the second shortcut


SJG • 5/26/15 – Clethra barbinervis • Summersweet in Area F: LEAVES and BUDS

From Missouri Botanical Garden: […] Clethra barbinervis, commonly called Japanese clethra, is a large, upright, deciduous shrub or small tree which typically grows 10-20′ tall and features horizontally drooping, terminal racemes (4-6″ long) of pleasantly fragrant white flowers which bloom in mid to late summer and serrated, glossy, dark green leaves which turn bright yellow (sometimes red) in autumn. Flowers are very attractive to butterflies and bees. Flower spikes give way to spikes of dark brown seed capsules which persist into winter and provide continuing interest. One of the most striking features of this shrub is the polished, grayish-brown bark which may exhibit exfoliation. Flower spikes are more horizontal and drooping and less fragrant than those of Clethra alnifolia.
Genus name comes from the Greek klethra the name for alder of which the leaves resemble.
Specific epithet means with veins barbed or bearded. […]

From wikipedia:  Clethra barbinervis is a species of flowering plant in the genus Clethra of the family Clethraceae, native to the far east, from eastern China, Korea, and Japan. It is an upright shrub growing to 3 metres (9.8 ft), with dark green leaves 5 cm (2 in) long, and racemes of small, fragrant, white flowers 15 cm (6 in) long in late summer and autumn. Mature specimens have attractive peeling bark. Though hardy, it requires a sheltered location in temperate regions. This plant has gained the Royal Horticultural Society’s Award of Garden Merit.

Interesting  article ‘Japanese Clethra: A Hidden Gem’ by Richard Schulhof from Arnold Arboretum: […] Like many plants in the Arboretum’s collections, this accession comes with an impressive pedigree, tracing back to Japan in 1886. In that year, William Penn Brooks, a Massachusetts native and valedictorian of the state agricultural college class of 1875, sent seeds of several species to the Arnold Arboretum. Brooks, then a teacher and administrator at Sapporo Agricultural School, found time to survey the surrounding countryside of Hokkaido for interesting plants, several of which came to enrich the Arboretum, including katsura tree (Cercidiphyllum japoni- cum) and hardy kiwi (Actinidia arguta). […]

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