Fresh, cold water spilled from a crack in the earth, and next to the natural bubbler hung several dented, metal cups. Our canteens were mostly full, but the steep hike up the mountain prompted unmet thirst. Also, our Korean colleagues told us the spring’s waters possessed qualities that would return us to our youth. Whatever it was we were quenching—perhaps each of us wanting something different—we eagerly dipped the cups and drank deeply.
Just before, we’d been traversing a wooded ridgeline, stepping along a trail that wandered through light forest cover and the occasional clearing wide enough to accommodate a helicopter. To reach the ridge, we’d ascended a series of steep zigzagging trails and rocky ways below the dense forest. The path from the ridge to the magical clearing where the mountain leaked was obvious. Below that point, the vegetation of trees, shrubs, grasses, and vines grew dense due to the rich, rocky, mucky soil and the spring’s reward. We plunged ahead eagerly, as our destination was not this fountain of youth but another magical something: Kirengeshoma palmata.
No matter how often you’ve seen a plant in cultivation, seeing it in the wild, in its own raw, unvarnished state, is special. In nature, the plant is stripped away from whatever pampering and primping the gardener gives it. You gain wonderful perspective of what the species and its natural environment amount to. Some plants are resplendent in nature, others demure; others an odd mixture of both. Regardless, these collective insights are invaluable to understanding a species’ in-situ proclivities, and can provide keys that unlock the secrets to successful ex-situ cultivation. It is why we collect in the wild, and why we were in the Republic of Korea on an expedition this past September and October. Despite wonderful Arboretum acquisitions from Korea in recent decades, this trip was notable because the last major Arnold Arboretum expedition to Korea was in 1977. We were thrilled to return.
No matter how often you’ve seen a plant in cultivation, seeing it in the wild, in its own raw, unvarnished state, is special
We were just below Baegunsan, a mountain 1222 meters high that lies at the southern edge of the peninsula, not far from the cities of Gwangyang and Suncheon. Besides us, our team comprised Professor Hui Kim of Mokpo University, and Mr. Hak-Gi Park and Mr. Jae-Jun Kim of the nearby Seoul National University’s (SNU) Nambu Forest Station. This natural area was under the management of SNU, and Mr. Park is one of the very best experts on the forests’ flora, having worked at the site for nearly 30 years. We were in excellent hands.
Why Kirengeshoma? Commonly called yellow wax bells, this herbaceous member of the Hydrangeaceae may seem an odd target for an Arnold Arboretum that prides itself in an almost exclusively woody plant collection. Although the species didn’t make it onto the infamous list of 395 targeted desiderata that comprise the Arboretum’s Campaign for the Living Collections, the hydrangea family is well represented. The genus is monotypic, with just one species—Kirengeshoma palmata—that occurs in the Republic of Korea, Japan, and China. (Note that some recognize plants of Korean provenance as a distinct species, K. koreana). The species possesses great conservation value, being rare regardless of country of origin. Our colleagues at China’s Zhejiang University (Professor Li Pan and graduate student Xu-Teng Zhang) are studying the genetic diversity among and across populations in each country. In fact, the two took Michael and assistant curator Miles Sax to one of the populations on China’s Tianmushan (Tianmu Mountain) in April 2024. It was during that trip that we decided to collaborate with them further on this species’ research project, acquiring germplasm and genetic samples during our trip to Korea and the 2024 trip to Japan.
Spotting the ground below were younger waxbell juveniles, just one or two years old, yet just as recognizable as their older kin.
While the youthful elixir exerted its effects, we pushed our way through the last of the brush to find ourselves at the upper reaches of the waxbell population. Under dense canopy above, the rounded plants formed mounded clumps, around three feet tall and just a bit wider. Though herbaceous, they masqueraded as woody shrubs in this environment. The broad leaves were large, bigger than one’s hand, with wide teeth along tattered margins. They were dull green, rather pockmarked, and had a prominent crisscrossing network of veins. Their coarse appearance contrasted sharply with other shrubs in the area— shiny, elegant, and narrow leaves of Lindera erythrocarpa; luscious, lustrous, and large leaves of Hydrangea macrophylla. Spotting the ground below were younger waxbell juveniles, just one or two years old, yet just as recognizable as their older kin.
The fruits of Kirengeshoma are bizarre. Earlier in the growing season, the yellow and waxy flowers are borne on terminal inflorescences. Each innocuous bloom possesses a delicate beauty, perhaps in part because of the juxtaposition with the rough and grainy foliage. But, we were now looking at the fruits—green balls that each bore several green antenna pointing up and out in several directions. The round seed heads were propped up on firm, wiry stems, as if transmitting radio waves across the forest floor. Were they cosplaying as gigantic ant heads, or rather diminutive extraterrestrials straight out of a 1950s comic strip? Maybe a bit of both. Inside the orbs, we’d find scores of damp, papery, winged seeds, hopefully just ripe enough that they were viable. In another month, the then-dried and opened capsules would start to shed the seeds to the wind.
In the garden, waxbells are placed within the ‘miffy’ category. The species can be needy with respect to requirements. Not too dry; not sopping wet. Never full sun or exposure to the elements; shade is best, but not too dark. Oh, and rich, organic soil. With those parameters needed for ideal cultivation, it can be rather easy to predict the native site’s characteristics. The plants in this population grew within 15 or so feet of either side of the mesic seep. It was easy to spot the large, coarse clumps—mature plants as well as smaller, young plants—down the undulating streamside. Even after a dry and stressful Korean summer, the brook raged downhill after plenty of precipitation from the remnants of tropical storm Pulasan. Although the plants’ roots anchored them into the soil, they looked shallow enough that during torrential rainfalls the dislodged plants would migrate downslope, just like the papery, winged seeds would later in the season as the wind dispersed them. Perhaps that is a cue to their niche—might they be keyed into that sort of disturbance?
In the steady hands of a propagator, they just might become future seedlings for ex-situ conservation
It was not just wet here, but also shady. The shade was provided by oaks (Quercus mongolica, Q. variabilis) and maples (Acer pictum), and quite a few Stewartia pseudocamellia. How often do you get to see this: a rare target species whose preferred habitat, in this population at least, was the understory of multi-stemmed Stewartias, each adorned with light-silver to raspberry-chocolate, patchy bark? Their robust trunks jogged back in forth as if they once dodged the shade in their first years as seedlings. What might this glade look like earlier in the season? we wondered. Do the two species bloom at the exact same time? Do the large, white, fallen blooms of the Stewartia scatter about to land on the wide leaves of Kirengeshoma, right next to the yellow, waxy bell flowers? We may need to return next summer to find out.
We surveyed from the top to the bottom of the stretch, taking copious notes and photographs, gathering individuals’ leaves for DNA extraction, and herbarium vouchers for posterity. We collected a total of sixteen fruits—rounding out our sixteenth collection of the trip—from which to extract seeds. In the steady hands of a propagator, they just might become future seedlings for ex-situ conservation. After wrapping up the last of our samples and gathering up our supplies, we paused to take in this magical spot one last time before we made the ascent past the spring and the ridgeline above.
Michael Dosmann is the Keeper of the Living Collections at the Arnold Arboretum and Chris Copeland is the Assistant Manager of Plant Production.
From “free” to “friend”…
Established in 1911 as the Bulletin of Popular Information, Arnoldia has long been a definitive forum for conversations about temperate woody plants and their landscapes. In 2022, we rolled out a new vision for the magazine as a vigorous forum for tales of plant exploration, behind-the-scenes glimpses of botanical research, and deep dives into the history of gardens, landscapes, and science. The new Arnoldia includes poetry, visual art, and literary essays, following the human imagination wherever it entangles with trees.
It takes resources to gather and nurture these new voices, and we depend on the support of our member-subscribers to make it possible. But membership means more: by becoming a member of the Arnold Arboretum, you help to keep our collection vibrant and our research and educational mission active. Through the pages of Arnoldia, you can take part in the life of this free-to-all landscape whether you live next door or an ocean away.