Sharing Our Research

They work to improve plant characteristics through breeding efforts and cultural techniques, enhance the sustainability of our horticulture processes, and innovate experimental land stewardship practices to conserve and cultivate native biodiversity. The impact of their work can be seen not only in our Gardens, but our global garden as well. They share their passion, knowledge, and expertise with audiences from around the world through research publications, trade journals, and magazines. Explore our most recent contributions below.

black and white illustration of southern red oak leaves and acorns

June 2022

Quest for southern red oak—north of the Mason-Dixon Line

Domestic plant exploration has increased as we work towards finding native and endangered alternatives to tree species, like the red oak (Quercus rubra), that are declining due to increased susceptibility to disease (in this case bacterial leaf scorch), or pests. One of our trips took us to southern oak populations (Quercus phellos, Quercus michauxii, and Quercus falcata) growing at the extreme edge of their northern limits, the woodlands and roadsides in southeastern Pennsylvania. 

Aiello, A. S. and Zale, P. J. Quest for southern red oak—north of the Mason-Dixon Line. Arnoldia 79 (2): 11–13.

white orchids in tall grass

April 2022

Choosing a favorable substrate to cultivate native orchids symbiotically – Examples using Goodyera tesselata and Platanthera blephariglottis

Native orchids in the United States are increasingly threatened due to factors like habitat loss and climate change. Scientists from Longwood Gardens and the Smithsonian Environmental Research Center teamed up to devise a series of experiments to solve this challenge using two species of Pennsylvania endangered native orchids, the white fringed orchid (Platanthera blephariglottis) and checkered rattlesnake plantain (Goodyera tesselata). This is the first in a series of studies following this line of research.

Zale, P.J., M.K. McCormick, and D.F. Whigham. 2022. Choosing a favorable substrate to cultivate native orchids symbiotically – Examples using Goodyera tesselata and Platanthera blephariglottis. HortScience. 57(5):634-642

red and green leaves of an Acer (maple) tree

October 2021

Maple History: an abundance of Acer - Maple cultivation in the Delaware Valley, part 1

A rich, well-researched chronicle of maple tree introductions in the Delaware Valley, reflecting the evolution in culture and international contact that occurred throughout Philadelphia’s history. Part One explores the initial exploration and cultivation of North American species starting from the late 1700’s through the introduction of European species by the middle of the 1800’s.

Aiello, A.S. Autumn/Fall 2021. Maple History: An Abundance of Acer - Maple Cultivation in the Delaware Valley, Part 1. The Maple Society Newsletter 31/3p. 28-34

sepia toned image of a person looking to their right

September 2021

Thomas Meehan: The Horticultural Poplularizer

Thomas Meehan was a man who committed his life to the advancement and improvement of the science and practice of horticulture. His passion for promoting both native and non-native species, exemplifies his visionary nature and offers a lens to the possibility and placement for both to exist in modern horticulture, over than a century later.

Aiello, A.S. 2021. Thomas Meehan: The Horticultural Poplularizer. Arnoldia 78(5-6):54-65.

close up of fountain grass

August 2021

Evaluation of Chemical Control Methods of Fountain Grass

Fountain grass (Pennisetum alopecuroideshas) been documented to grow outside of cultivation and reported to demonstrate invasive tendencies, however there is limited research on the optimal methods to use on fountain grass in natural areas. Results from this study support an approach that combines herbicide treatment alongside restorative plantings of native plants to help future invasive plant pressure.

Thomas, J. and M. Taylor August 2021. Evaluation of Chemical Control Methods of Fountain Grass. HortTechnology 31(4)382-384.

selections of tools for plant study laid out on a tree stump

July 2021

Thinking in Ecosystem Time

Our Land Stewardship and Ecology team takes actions to set things in motion—preparing a place for new growth, planting a seed we hope will spread—and a whole career may pass before the result is seen. To see both the fast and the slow changes we need data. Utilizing new technologies were can reference maps of where native plant populations thrive and where invasive species are, speeding the management planning process. Just as importantly, data describing how things are now will, in turn, become a record of how things were in the past—helping us and future land stewards to see change. Whether that change is a thriving rare plant population, a management practice that needs adjustment to maximize its effectiveness, or growth of a newly planted forest area, this new system helps us to visualize changes both fast and slow—and to think in ecosystem time.

Johnson, L.R. and Kristie Lane Anderson. 2021. Thinking in Ecosystem Time. Longwood Chimes 303:32-37.

two people kneeling on the ground planting native orchids

July 2021

Native orchid conservation at Longwood Gardens

Pennsylvania is home to 59 orchid taxa, half of which are of conservation concern. Longwood Gardens Science division is combining horticultural science with native species ecology to develop protocols for producing these orchids, in order to first preserve and then build up populations to restore into their native habitats. This whole system approach has met with incredible success and is now expanding to support terrestrial orchid conservation efforts locally, regionally and worldwide.

Zale, P.J. July 2021. Native orchid conservation at Longwood Gardens. Orchids. The American Orchid Society Magazine. 501-504

collage including a yard stick, photo of a person hiking, image of mountains

July 2021

When Borders Close

International plant exploration offers scientists the opportunity to collaborate with colleagues from around the world to explore uncharted areas and discover new plants, in a combined effort for us to continue understand the complex world we live in and how we can work together to preserve it. The pandemic halted these international endeavors, for a time, and redirected our focus to native plant systems and plants.

Zale, P. 2021. When Borders Close. Longwood Chimes 303:16-17.

clump of green acer leaves against a white background

June 2021

Distinguising Franchet's, pungent and Qinling maples

Twenty percent of maple species are threatened with extinction, however the species most in need of conservation are being the least helped. Two maple species serve as a model to support this assertion and the authors propose that future selection of species for cultivation should prioritize a species need for conservation as a criterion. 

Aiello, A.S. and D. Crowley. June 2021. Distinguishing Franchet's, pungent and Qinling maples. The Plant Review p. 57-59. 

urban garden with two black metal chairs and table

July 2020

Conceptualizing social-ecological drivers of change in urban forest patches

This urban forest patch model serves as a starting point to systematically examine key social ecological questions about urban forest patches, whether location specific or on a global scale. This model was developed with temperate forested regions in mind, however with some modifications, this model could be applied to other urbanized forested regions globally.

Johnson, L.R., M.L. Johnson, M.F.J. Aronson, L.K. Campbell, M.E. Carr, M. Clarke, V. D'Amico, L. Darling, T. Erker, R.T. Fahey, K.L. King, K. Lautar, D.H. Locke, A.T. Morzillo, S. Pincetl, L. Rhodes, J.P. Schmit, L. Scott, N.F. Sonti. 2021. Conceptualizing social-ecological drivers of change in urban forest patches. Urban Ecosystems. 24,633-648.

Science at Longwood

Horticulture is driven by a diligent, research-based pursuit that artfully innovates how one can celebrate and coexist with the natural world in order to ensure and depict its beauty in perpetuity for generations to come. Their work specializes in the following four disciplines: Conservation Horticulture & Collections, Land Stewardship and Ecology, Agriculture, Soils and Compost and Floriculture Production.

Additional Publications

Explore even more articles, books, and publications by our Horticulture Team.