One of the staple shrubs for native plant gardens is the lovely summersweet (Clethra alnifolia). Its ample charms rightfully warrant it the status of a mainstay. Not encountered as often, however, is its Japanese counterpart, the graceful Clethra barbinervis. Japanese summersweet is tall and graceful where our native is shorter and squatter. The lovely fragrance for which they are both named remains, though.
Japanese summersweet is a large airy shrub which can attain heights of 10' to 15' with an upright oval habit. The foliage is longer than our native, occasionally to 5" long and deep, dark green with serrated edges. The fall color is typically an excellent wine red, but some forms exhibit more yellow than red. The small 0.25" flowers are held on long, 4" to 6", drooping racemes in July and August. The flower racemes are borne at the tips of all the branches in clusters of three to five, literally covering the plants in flower. The flowers are as fragrant or even possibly more fragrant than the native, making Japanese summersweet a highly desirable garden plant. The bark of Clethra barbinervis is truly one of the most beautiful of all shrubs. The cinnamon colored bark peels off to show smooth patches of tan to grey. Altogether Japanese summersweet offers the garden something in every season.
This four season shrub prefers a moist, fertile, rich soil but will take less than ideal conditions. It grows best in light filtered shade but will tolerate full sun especially if given adequate moisture. In colder regions there may be some tip death during the first year or two of establishment. Japanese summersweet can be pruned in late winter for shape if desired, but will rarely need it. It may sucker around its base, but not usually to a great extent. Because of its beautiful bark, it can be limbed up like a small tree to better display this characteristic. In very hot, dry locations spider mites can sometimes be a problem.
With multiple seasons of interest and exquisite fragrance, Japanese summersweet deserves a place of honor in the landscape. Along woodland paths or as a specimen in a shady garden, Clethra barbinervis will shine. Wherever it is planted, Japanese summersweet will provide long days of beauty to gardeners from the ocean to the mountains. – Mark Weathington, Assistant Director and Curator of Collections
This month be sure to visit the Annual Color Trials, which are in their full glory in their new permanent location on the south area of the Arboretum.
Aralia elata 'Silver Umbrella' – variegated Japanese angelica tree
Callicarpa formosana – Formosan beautyberry
Hibiscus coccineus f. alba – white scarlet mallow
Hedychium 'While Starburst' – hardy ginger-lily
Crinum cultivars – crinum-lily
Dahlia 'Knockout' – garden dahlia
Zephyranthes species and cultivars – rain lily
Klein-Pringle White Garden
Eupatorium purpureum 'Joe White' – white Joe-pye weed
Phlox paniculata 'David' – garden phlox
Abelia ×grandiflora 'Rose Creek' – glossy abelia
Sedum telephium 'Matrona' – common orpine
Cosmos sulphureus – sulphur cosmos
Echinacea purpurea 'Merlot' – eastern purple coneflower
Helianthus salicifolius – willow-leaf sunflower
Hemerocallis 'Autumn Prince' – daylily
Lilium formosanum – Formosa lily
Scree Garden and Xeric Garden
Aloe cooperi – Cooper's grass aloe
Callistemon brachyandrus – prickly bottlebrush
Chrysactinia mexicana – damianita
Sedum 'Lajos' – sedum
Visit Showtimes for a much more detailed listing of what's in flower in August at the JCRA.
It's your garden. We invite you to visit often. – Nancy Doubrava, Interpretive Specialist
Guided Tours – August 1, 8, 15, 22, and 29, 2010 (Sundays) – 2:00 PM – Free
We invite you and your friends to join us for free guided tours through the Arboretum. Learn about the Arboretum's history, plants, and more. Tours are available to the public free of charge every Sunday (with few exceptions) at 2:00 PM from March–October. Tours are led by a dedicated group of volunteers and last approximately one hour (rain or shine).
Plantsmen's Tour – August 10, 2010 (Tuesday) – 9:00 AM – Free
"Summer Perennials" led by Mark Weathington, Assistant Director and Curator of Collections. Take a tour of the hot colors and wonderful textures along our Perennial Border and throughout the Arboretum to learn what you can grow for late summer interest.
Please visit the "Calendar of Events" section on the JCRA Web site for a complete listing of our upcoming programs.
Two new videos were recorded for the Members Only section on the Arboretum's Web site in July.
Content in the Members Only section is password protected and is only available to Arboretum members. In order to access these special features, members need to know the password that was printed on the label of the latest Friends of the Arboretum Newsletter or included at the end of the e-mail with the latest monthly JCRA e-Update attached to it. If you receive the JCRA e-Updates via e-mail, the end of the e-mail is after Chris's signature line, not at the bottom of the e-Update itself. The user name needed to log in is always "jcra."
JC Raulston Arboretum e-Updates are published electronically every month for everyone interested in the Arboretum and are e-mailed to the Arboretum's members. If you are a member and need to update your contact information or wish to be removed from this mailing, please contact Judy Morgan-Davis.
© August 2010, JC Raulston Arboretum