October was quiet. The headhouse at the Dana Greenhouses was still, except for the dim hum of the radio, a necessity for an almost empty building. In previous years, the same location would have been marked with a cacophony of sounds, the door thrown ajar as Arnold Arboretum plant collectors eagerly arrived to unpack their hard-earned seeds and plants. Sieves and colanders would have rattled against the center worktable as plant production staff removed fruit pulp from each seed, and everyone would be talking about new and exciting acquisitions. Seed cataloging and cleaning is a departmental undertaking, sometimes lasting the entirety of fall and into early winter.

This annual activity has occurred at an invigorated level since 2015, when the Arboretum launched the Campaign for the Living Collections, a strategic ten-year initiative to increase the biodiversity and conservation holdings of our living collections by adding nearly four hundred wild-collected taxa that were not already growing in our landscape. As part of the campaign, staff organized and executed as many as five expeditions annually, traveling to locations in northern Idaho, central China, the country of Georgia, and elsewhere.

I have participated in two of those expeditions myself: one to the Ozarks and another to northern Illinois and Wisconsin. It was rewarding to engage in the full process, from planning expedition logistics and obtaining permits to harvesting in the field and then processing seed back at the Dana Greenhouses. The collection that stands out most from my two experiences was of the endangered seaside alder (Alnus maritima ssp. oklahomensis). I collaborated with Kea Woodruff, then the Arboretum’s plant growth facilities manager, to collect seed from two plants growing along the Blue River in Tishomingo, Oklahoma. We were guided by local experts. This subspecies of the seaside alder has only been documented in three other locations in the wild, all near the Blue River. (The two other subspecies also have extremely restricted ranges—one occurs in a single location in northwestern Georgia, the other comprises scattered populations on the Delmarva Peninsula of Delaware and Maryland.) For me, this collection brought home the purpose of  the campaign and the urgency of preserving threatened taxa.

In the fall of 2020, however, those collections ceased due to the pandemic. Planned expeditions to China, Japan, and South Korea were postponed. In the headhouse of the Dana Greenhouses, the difference was striking. Only two or three members of the plant production department worked on-site on any given weekday, in an effort to de-densify our workspace and to allow staff to care for children who were completing schoolwork from home. This revised schedule continues into the new year. Other nonessential staff are not permitted inside the building. Now, our team hears only the quiet sounds of greenhouse doors opening as we check the facilities, monitor plants for water, and scout for insect pests and diseases. We hear the clatter of containers being placed on potting benches as we prepare to transplant seedlings and the swish of cutting media components being mixed as we get ready for winter hardwood cutting season. We occasionally share the same workspace, but only brief, work-related interactions can take place. Our team meetings are now virtual.

The production cycle for plants already in the greenhouses and nurseries has not significantly slowed this year, although the headhouse tables are bare: no collection sheets from the expeditions strewn about, no bags of fermenting berries or cones to go through. During this altered time, as we have continued with usual greenhouse and nursery tasks, the plant production department has had the opportunity to refocus our direction on other activities. We have made enormous strides to integrate our workflows into the Landscape Management System, a new digital tool developed at the Arboretum, which combines horticulture and curation efforts through mobile applications and an internal website.

Photograph of masked horticulturist preparing grafts
When new plant material arrives at the Dana Greenhouses, staff begin a detailed process of record keeping. New innovations have streamlined the process. Sean Halloran readies softwood cuttings and will note rooting observations using a newly developed mobile application in spring. Tiffany Enzenbacher

One component of this system, PropManager, will eventually replace the use of handwritten propagation cards, which are used to record treatments and results for propagation attempts, including for seeds that return from expeditions. Currently, when seeds arrive, staff record propagation methods and experiments on these cards. While some seeds can be sown immediately, others must undergo periods of cold or warmth. Others require treatments to weaken the seedcoat: sandpaper or an acidic solution. Data from propagation cards are then entered into BG-BASE, the Arboretum’s plant records database. Then, as germination, transplanting, and other events occur, the cards are updated, corresponding data are input into BG-BASE, and the cards are refiled into a binder. PropManager will allow us to create a digital “card” on a mobile device and record events in real time. We observed how inefficient the physical card system was when Sean Halloran, our plant propagator, had to transport boxes of binders to and from his home as he toggled between remote and on-site work this spring.

Our team has also completed work that will help us to map, track, and communicate about plants in our nurseries using additional Landscape Management System tools. Chris Copeland, our greenhouse horticulturist, worked with members of the Landscape Management System team to acquire and upload locations of over 250 nursery plants. Specimens are now visible on a dynamic map, and we can easily picture spatial patterns and adjust maintenance of the next generation of Arboretum plants. Likewise, when horticulture staff inherit a tree after it has been transplanted into the landscape, they can use this new set of tools to determine noteworthy events that transpired during the tree’s early life.

We are also working with Mike O’Neal, the director of BG-BASE, to analyze information about our repropagation attempts. Each year we duplicate hundreds of historic Arboretum plants through vegetative propagation—a process whereby resulting progeny are genetically identical to the original. Halloran and O’Neal are in the process of creating BG-BASE summary reports. The result will help determine whether the repropagation of a specimen in the landscape is complete. Instead of Halloran spending weeks at his desk writing code and manually sleuthing through BG-BASE tables, he will be able to run a quick query to have access to all the data needed.

The scene at the Dana Greenhouse is certainly different than it was in autumn 2019. That year, we processed over 150 seedlots and mailed surplus material to over a dozen collaborating institutions. Yet the unplanned reprieve from receiving campaign material has allowed our plant production team to collaborate on projects that would have otherwise progressed incrementally over multiple years. We are now better equipped than ever and prepared for the onslaught of new seed collected by Arboretum explorers who are eager to be back out in the field.

Tiffany Enzenbacher is manager of plant production at the Arnold Arboretum.

Citation: Enzenbacher, T. 2021. An Unusual Autumn at the Dana Greenhouses. Arnoldia, 78(3): 7–9.

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.

For more tree-entangled art, science, and writing, subscribe to Arnoldia by becoming a member of the Arnold Arboretum.