Rhododendrons
at Holden Forests & Gardens
Holden Forests & Gardens is a global leader in Rhododendron conservation, research, and breeding.
While stewarding one of the most extensive collections of Rhododendron in the world at our David G. Leach Research Station, the experts at Holden are pioneering innovative research and conservation efforts to enhance the resilience and protect the biodiversity of Rhododendron species worldwide.
New! Holden’s® Rhododendrons
Holden Forests & Gardens is proud to introduce our new Rhododendron hybrids, bred for beauty and resilience.
Created by Dr. Stephen Krebs, former Leach Research Station director, these stunning varieties are now available through Briggs Nursery: Holden’s® Fuchsia, Holden’s® Peach, Holden’s® Pink, Holden’s® Pink Flare, and Holden’s® Red.
These hybrids have improved resistance to the root rot disease caused by Phytophthora cinnamomi, are hardy in Zone 5, and have exceptional ornamental appeal! Growers contact Briggs Nursery for purchasing information. Gardeners and landscapers should request them at your local nursery or garden center.
These new hybrids join other rhododendrons on the market bearing the Holden name. ‘Holden’s Solar Flair’ and ‘HOLDEN52’ (sold as Southgate® and Splendor™) were bred at Holden and introduced in the early 2010’s. And the rhododendron simply named ‘Holden’ was named for the arboretum by long-time friend and rhododendron breeder, Tony Shammarello, in the mid-20th Century.
Our Living Collection
Rhododendrons are best known for growing in home gardens and botanic gardens, but they are naturally occurring worldwide—even here in Ohio. The wild species are threatened by climate change and environmental degradation in their natural habitats, so their conservation is critical. At Holden’s David G. Leach Research Station, we’re building a living collection of wild origin plants for conservation, research, and breeding. The 30-acre property in Madison, Ohio, houses a world class collection of rhododendrons, azaleas, and other choice woody plants. Additionally, the Holden Arboretum is home to the Rhododendron Discovery Garden and Layer Rhododendron Garden, featuring 80 years of collections and conservation work. Working with Botanic Gardens Conservation International and the Global Conservation Consortium for Rhododendron, we’re committed to conserving Ohio’s native rhododendrons and azaleas, U.S. threatened species (Rhododendron prunifolium and R. flammeum), and other species from the U.S. and abroad.
Learn more about Rhododendron collection curation at Holden Forests & Gardens.
Understanding Plant Adaptation
Rhododendrons are not only of conservation and horticultural interest; HF&G is developing the genus Rhododendron as a model study system to explore the evolution of woody plant biodiversity. Our researchers study the physiological and genetic differences between species from warm and cold climates, especially regarding which traits make each species well-suited for specific environments. Our team’s findings are interesting beyond just rhododendrons, shedding light on how plants in general can adapt to challenges such as drought, heat, and frost, and the genetic variation within species that drives evolution through natural selection.
Active Rhododendron research projects:
- Local adaptation to climate in Rhododendron minus
- Leaf and flower heat tolerance of cold hardy Rhododendron species
From the Get Growing Blog
Teaming Up to Find the Pinxterbloom Azalea
by Kara Grady | May 29, 2024
While our coworkers celebrated spring at the arboretum, May 1st found Connor and I, as well as Greg Payton Kady Wilson of the Dawes Arboretum, in Shawnee State Forest in Southern Ohio. We had come not only to try and find a pure Rhododendron periclymenoides, the Pinxterbloom Azalea, but to… Keep reading.
Meet the Future of Rhododendron Research
by Juliana S. Medeiros, PhD | May 24, 2024
Members of the Medeiros Lab in the Holden research department organized an Early Career Researcher Mini-Conference and research poster session at the American Rhododendron Society Annual Convention which took place in Bellingham, Washington April 30-May 5, 2024. The Mini-conference was organized by Holden Scientist Dr. Juliana Medeiros and Holden graduate… Keep reading.
Saving a Rare Rhododendron Species
by Kara Grady | May 21, 2024
A brisk day in March found me driving up to Lantern Court, the historic home of the Corning family, whose head began the first rhododendron collection and gardens at Holden Arboretum. I’ve always had a deep fascination with historic buildings and was excited to embark on my first tour of… Keep reading.
Ohio’s Native Rhododendrons
by Kara Grady | April 2, 2024
I love native plants, especially the prairie plants of my home state, Iowa. So when I first moved out to Ohio, I knew I’d be learning the new names and faces of the region’s more easternly plant species. What I didn’t realize was that a whole new genus was waiting… Keep reading.
Rhododendron minus: A colorful mystery wrapped in a riddle
by Juliana S. Medeiros, PhD | November 29, 2023
Rhododendron minus is a woody evergreen shrub native to the southeastern United States, with a range that extends from North Carolina and Tennessee south into Georgia and Alabama. Across this range, R. minus exhibits higher than average variation in traits like flower color, from deep pink to snowy white. Scientists… Keep reading.
Meet our Rhododendron Experts
Contact us
Media please contact:
Stacey Vaselaney
[email protected]
(216)905-0908
Leach Research Station site and collection use:
Connor Ryan
Rhododendron Collections Manager
[email protected]
Holden Forests & Gardens is made up of two of Northeast Ohio’s most important environmental and cultural institutions—the Holden Arboretum and Cleveland Botanical Garden—whose mission is to connect people with the wonder, beauty, and value of trees and plants, to inspire action for healthy communities. One of the largest public gardens in the country, Holden Forests & Gardens has over 22,000 member households and an annual attendance of over 300,000 for whom we strive to provide inspirational and educational visitor experiences. Holden’s science, conservation, and urban forestry work is widely acclaimed and helping to save native trees in the Great Lakes region and beyond.
