Pterostyrax hispidus, the Fragrant Epaulette

Pamela J. Thompson

began my relationship with fragrant epau- bronze-chartreuse ornaments. These are most lette tree ( hispidus) when long- evident once the have dropped, looking I time Arboretum supporter and volunteer somewhat reminiscent of dangling sections Elise Sigel brought me a lanky, homely speci- of a DNA helix. men, wondering if I could give it a home. Elise The Arboretum’s accession records for Ptero- couldn’t recall its full (some hispidus reveal a history of human inter- sort of styrax?), and I failed to record even this. est and persistence in growing this . The I planted it in my Milton garden, not knowing Arboretum acquired its first accession in 1880 what I had, or how it might grow. Though I from J. Veitch and Son in England. Over the next don’t widely recommend this blind-faith land- 130 years, the Arboretum acquired and scape design strategy, in this case I’ve been , including the 1892 accession collected delighted with the results. by Sargent in Japan. Many of these acquisitions, is a tree native though, were of garden origin or uncertain prov- to Japan, specifically in the forested mountains of enance. The Arboretum currently has 3 acces- Honshu, Shikoku, and Kyushu. A member of the sions (9 total plants) of Pterostyrax hispidus. storax family (), it is closely related Accession 218-60 came to the Arboretum as to the silverbells (). Though it can grow from the University of British Columbia, almost as broad as tall, reaching up to 50 feet Canada, but with uncertain provenance. Acces- (15.2 meters) in height and 40 feet (12.2 meters) sion 241-2008, received from Chiba University in width as a tree, it is more often noted as a large in Japan as seed, was wild collected in 2006 multi-stemmed reaching about 25 feet tall. in Gunma Prefecture, Kanto District, about In fact, it was the shrub form that Arboretum 20 miles northwest of Tokyo. The third acces- Director C. S. Sargent first saw in 1892 growing sion, 843-76, came from the Academy of Sci- “… wild in Japan on the banks of a stream among ences, Vacratot, Hungary, in 1976 and is also of the mountains above Fukushima.” uncertain provenance. The leaves of fragrant epaulette tree are Though it received the Royal Horticultural oblong with a tapered point and have finely- Society’s Award of Garden Merit in 1993, Ptero- toothed margins. They range from 3 to 7 inches styrax hispidus remains uncommon in the nurs- (7.6 to 17.8 centimeters) long and 2 to 4 inches ery trade. It is often listed as hardy to USDA (5.1 to 10.2 centimeters) wide. Handsomely Zone 4 (average annual minimum temperature bright green above and gray-green below in -20 to -30°F), but Arboretum observations over spring and summer, the leaves turn yellow- the years indicate that this may be only green to yellow in autumn before dropping. A marginally cold hardy and is also intolerant of truly remarkable feature of this plant is its pro- drought. Notes about leader dieback and vigor- fusion of 7- to 9-inch-long panicles of fringed, ous basal sprouting imply that this species is downward facing, white that appear more likely to grow as a multi-stemmed shrub in mid to late June (in the Boston area). Hang- in the Boston area. ing below the leaves, the clusters sway As the snow has melted from around my now in the breeze, attracting multitudes of polli- 15-foot-tall tree, I can see that several lower nators and giving off a delicate sweet scent. lateral branches have snapped off at the trunk The inflorescences, reminiscent of the fringed union from the weight of this winter’s snow. epaulettes that once adorned the shoulders of Even so, it is a plant worth trying in southern military uniforms as a show of rank, give fra- New England, even if only on blind faith. grant epaulette tree its common name. Through the summer, long clusters of indehiscent, bris- Pamela J. Thompson is Manager of Adult Education tly dry drupes develop, adorning the tree like at the Arnold Arboretum.