Distylium Coppertone™, a Newly Available Evergreen Shrub, is Attractive in All Seasons
By Corinne Kennedy
A very young Distylium Coppertone™, in the Seattle Japanese Garden. It was planted in 2022 at the south end of the Garden’s pond. (photo: Corinne Kennedy, February 2023).
I was excited to learn last winter that Peter Putnicki, the Seattle Japanese Garden’s Senior Gardener, had added a genus of noteworthy but rarely planted evergreen shrubs to our Garden. That genus is Distylium, called “the best new plant you’ve never heard of” by Dr. Michael Dirr, horticulturist, plant breeder, Professor Emeritus at the University of Georgia, and director of the university’s botanical garden:
Virtually unknown, unidentifiable, unheralded and unloved, except to the cadre of collectors who desire one of every plant—are evergreen members of the Hamamelidaceae witch hazel family, the species sporting small apetalous [lacking petals] red flowers from the leaf axils in late winter-early spring, positioned among blue-green to lustrous dark green foliage.1
Fortunately, Distylium Coppertone™, an attractive new hybrid of this genus, was one of the two cultivars that Pete chose to add to our Garden.
I had learned about the genus Distylium in the late 1990s, when I worked at a large retail nursery known for its comprehensive selection of trees and shrubs. For several years the nursery ordered plants from Piroche Plants, a British Columbia wholesale nursery that was importing woody plants from China, marketed as the WILD DRAGON™ series, that hadn’t previously been available. Among them were two Distylium species, Distylium racemosum and Distylium myricoides, commonly known as isu trees.
Dirr had also ordered the two species—for trial at the University of Georgia’s Horticulture Farm—and ultimately became instrumental in what he described as their “transformation via breeding to functional, beautiful, easily grown landscape plants.” His goal was to create a hybrid plant that could replace the ubiquitous, problematic, and boring evergreen shrubs planted throughout the south and in much of the U.S. With his characteristic sardonic wit, he referred to the plants he wanted to replace—including hollies (Ilex), junipers (Juniperus), boxwoods (Buxus), Indian hawthorns (Rhaphiolepis), Euonymus (Euonymus), and English laurels (Prunus laurocerasus)—as “green meatballs.”
In this article, I’ll first provide brief descriptions of the newly developed Distylium hybrids and specifically the two hybrids recently planted in our Garden. For those who are interested, I’ll end with the story of how they were developed.
The Distylium Hybrids:
Distylium hybrids are easy-care evergreen shrubs with attractive blue-green or glossy dark green leaves. Compact growing, they are resistant to disease, insects, and damage from deer and rabbits. They grow well in full sun or part shade, and are heat and drought tolerant. They will also grow in wet soils. Though they require minimal maintenance and very little pruning, they take well to pruning if compactness or hedging is required. Light tip pruning will produce more compact plants. Clusters of reddish-maroon flowers appear in the leaf axils in late winter or early spring. Though lacking true petals and not considered showy, the small flowers are interesting when viewed from up close. Seeds are small brown capsules and are not invasive.
The newly available hybrids are likely to prove useful in Japanese-style gardens, where evergreen shrubs are essential structural elements. Unfortunately, when the Seattle Japanese Garden was constructed in 1960, its creators were unable to source many of the broadleaf evergreens used in the gardens of Japan. I’m hopeful that one or more of the new Distylium hybrids will prove to be important evergreens within our Garden.
Distylium Coppertone™, planted next to the pond in the Seattle Japanese Garden. This photo was taken in February 2023, before the emergence of new growth. (photo: Corinne Kennedy).
Distylium Coppertone™2 is planted in Area V of the Seattle Japanese Garden, at the south end of the pond—just north of the steps to the boat-launching stone.2 Coppertone™ is a compact evergreen shrub with a spreading-mounded habit and small, reddish, late winter or early spring flowers. New foliage emerges in spring with a striking blend of copper, bronze and red tones before maturing to a matte bluish green. Hardy to USDA Zone 7b (minimum temperature 5 degrees Fahrenheit), its mature size is 3-4 ft. tall by 4-5 ft. wide. Coppertone™ works well as an ornamental accent or foundation plant and as a low-growing hedge.
Colorful new growth of Distylium Coppertone™. (photo: Bailey Nurseries)
The Seattle Japanese Garden’s other hybrid, Distylium ‘Vintage Jade’, was planted in 2022 below the pagoda in the Garden’s mountain area, Area Y. (In this drier, shadier location, the young plant is struggling and may need to be moved to a better location elsewhere.) It has glossy dark green leaves, a low but broadly arching habit, and reddish-maroon flowers in late winter or early spring. The parent plant was 2.25 ft. tall by 8 ft. wide in less than ten years. ‘Vintage Jade’ is hardier than Coppertone™ and may be adaptable to Zone 6b (minimum temperature -5 degrees Fahrenheit). With its wide-spreading habit, it works well as a groundcover on banks or in other large areas.
Two Distylium species and Development of the Hybrids:
This final section is for those readers who, like me, are excited about newly available plants and fascinated by the stories of how they were created or came to be available.
Botanical drawing of Distylium racemosum. (image: Phillipp Franz von Siebold and Joseph Gerhard Zuccarini, in Flora Japonica, 1870; Wikimedia Commons)
There are eighteen species in the genus Distylium, most endemic to China. Only two species, D. racemosum, a 60-foot-tall tree, and D. myricoides, a large shrub (10 ft. tall by 15 ft. wide), have been occasionally available in the nursery trade. Though generally smaller under cultivation, neither has been commercially successful. Yet both have attractive characteristics that have proved to be useful in developing more garden-worthy plants. The former has glossy dark green leaves, elliptic in shape. In Dirr’s trials it has proved to be very adaptable—cold, heat, and drought tolerant. And the latter, though a lower-elevation and less hardy plant, was praised by Dirr for its aesthetic qualities: “fine-textured, narrow leaves, distinctly blue-green, on wide-spreading, horizontally arching branches that layer upon each other.”
Although most Distylium species are native to China, Distylium racemosum is native to Japan. Known as isu-no-ki, it was sometimes planted in gardens, but was more highly valued for its fine-grained wood, used in construction, in crafts, and for making furniture.
The small, unopened flower buds of Distylium racemosum. (photo: KENPEI, April 2008; Creative Commons Attribution-Share Alike 3.0 Unported license)
As mentioned above, Dr. Dirr ordered a shipment of the two Distylium species and another plant, Distylium myricoides ‘Emerald Elf’, that had been promoted as being more compact. Unfortunately, all grew “large and unkempt,” offering little of interest to gardeners or the nursery industry. Nonetheless, his shipment also included a plant that appeared to be a hybrid, later proved by genetic testing. Its seeds were collected in 2005, germinated, and grown on in containers. Twenty-one of the seedlings were selected for further study, and planted out in the ground.
Finally, during the next decade, three hybrids (Emerald Heights®, Blue Cascade®, and ‘Vintage Jade’) were named, patented and introduced to the trade through the work of Dirr and two partners, Jeff Beasley and Mark Griffith, at their research facility, Plant Introductions Inc. (Formed in 2007 to breed and evaluate new ornamental plants, it was sold in 2015 to Bailey’s Nursery, St. Paul, MN.). From those three initial hybrids, another three introductions were developed—Coppertone™, Linebacker™, and Cinnamon Girl®. All are broadleaf evergreen shrubs, varying in habit and size. Since then, other breeders and institutions have created many additional compact, easy-care, and attractive Distylium hybrids.
I look forward to seeing how well the two hybrids planted in the Seattle Japanese Garden in 2022 will adapt to its challenging clay soils. In fact, I’m planning to choose one of the hybrids available at local nurseries to plant in the wet clay soil of my own garden. But the newly available hybrids of “the best new plant you’ve never heard of” should also prove attractive to those of you who are fortunate to garden in much better soils. We can all benefit from re-evaluating and replacing some of the shrubs that Dr. Michael Dirr scorned as “green meatballs.”
FOOTNOTES:
All quotations by Michael Dirr are from his 2015 article, “Distylium: The Best New Plant You’ve Never Heard of,” at growertalks.com.
Coppertone™ is this hybrid’s trademark name, the name most likely to be used by nurseries and their customers. Like most recently created trademarked and registered plants, its cultivar name, indicated with single quotation marks, contains coded information but is essentially incomprehensible. The sequence of information that follows includes Coppertone’s cultivar name, plant patent number, and the series concept used in marketing: ‘PIIDIST-III’, PP25 304, First Editions®.
Corinne Kennedy is a Garden Guide, a frequent contributor to the Seattle Japanese Garden blog, and retired garden designer.