Cracking a Shellbark Case

As a rule, trees are always redder on the other side of the fence—the next town over or several hours north. Maples (Acer) are beginning to turn extravagant shades at the Arboretum, yet the leaf-lorn, like myself, always wonder whether the show will completely materialize, or whether a storm, like the one that whipped through last weekend, will deliver the terminal blow, stripping all promise to the sidewalk. Nevertheless, even a modest shift—green to brittle brown—can move the klieg light, bringing a backstage actor into stardom. This is now happening with the hickories (Carya), which though humble for much of the year, reliably turn the color of clear Kansas sunshine in the fall, even when everything else goes awry.

One of these hickories, a handsome shellbark (Carya laciniosa, accession 12897*A, formerly 22866*A), guards the intersection between the greenhouse driveway and Bussey Hill Road. The leaves are becoming evermore gilded, but even so, I’ve been perennially frustrated with this individual. If the Arboretum is a collection of trees (and shrubs and vines), it is also a collection of documentation. The name on a plant tag is important, but it is just as important—in some cases, almost more important—to known where the plant comes from. The more details, the better. Yet no matter how impressive the barrel-shaped trunk of this shellbark hickory, and no matter how saturated the fall color often becomes, the records have long indicated that it was accessioned as an existing plant in 1950—provenance unknown.

This uncertainty was irksome. Unlike the white oak (Quercus alba, accession 346-2010*A) that Michael Dosmann wrote about in the most recent issue of Arnoldia (volume 76, issue 1)—where he described extracting a core sample and counting the annual growth rings to prove that the tree was more than two hundred year old—all evidence suggested that this shellbark was intentionally planted, not a pre-Arboretum remnant. For one thing, shellbark hickories are native further west, arrayed widely along the Mississippi and Ohio Rivers, but nowhere near the Charles. Moreover, the landscape placement was too strategic, suggesting the tree had been planted after the Arboretum roadways were laid in the 1880s.

Matters might have remained there (ambiguous and anonymous) if not for the Arboretum archives. Earlier this summer, I was perusing black-and-white photographs in the library, hunting for images of hickories taken by field botanists in Missouri, Mississippi, and elsewhere. The photographs are organized taxonomically, and historic views from the Arboretum are interspersed with the others. By happenstance, one pair of photographs depicted an individual shellbark hickory growing on the edge of Bussey Hill Road, with the characteristic glacial topography of the North Woods visible in the background. The winter silhouette was unmistakable—even the branching structure could be matched to the greenhouse sentinel—but of greater importance, on the back of the photographs, which were snapped in the first leafless months of 1928, the typewritten caption included an accession number.

With this information, we could reestablish that this shellbark hickory arrived at the Arboretum in 1874, sent as seed from an Ohio printer-turned-farmer-turned-horticulturist named William Hampton. At that point, the Arboretum, which was founded in 1872, had acquired plant material from fewer than forty individuals and institutions. The only sources that supplied more plant material than Hampton (who sent thirty-five accessions during those three years) were the Royal Botanical Gardens, Kew, and the Imperial Botanical Garden at St. Petersburg. The rediscovery of this record now places this hickory as one of eighteen accessions that remain from this early period, making it one of the oldest plants of known provenance in the Arboretum collection.

It would, of course, be nice to know more than a date and source. Sargent mentioned Hampton in his first report as director in 1874, acknowledging that Hampton provided “large and full collections of seeds of the trees and shrubs of Ohio and the neighboring States.” In terms of ascertaining a wild-collected provenance, however, this description is not very precise. Yet it’s worth noting that Hampton was especially attentive to the flora of Hardin County, where he lived, and that he published a checklist of native species in 1879, which included shellbark hickories among the rank. Sargent, writing four decades later, credited this county as the origin for seed of another species that Hampton sent. While it seems likely that the shellbark would have been collected locally as well, it will take a bit more scrounging (and likely another dose of serendipity) to confirm that hunch.

In the meantime, the shellbark show is beginning. Leaves are turning, and the nut-like fruit, which were produced abundantly this year, have already turned to squirrel-induced mulch on the chipped path that cuts beneath the tree. When I dig my toe into this litter, looking for anything the foragers have left behind, I can almost imagine Hampton, filling a basket or sack beneath an equally impressive tree—perhaps one growing on the back of his large Ohio farm—knowing that he had something good for the mail.

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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.

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