The Authority on Genus Rhododendron

David G. Leach Research Station

The Leach Station was a gift to Holden from Dr. David Leach, a world authority on genus Rhododendron. Located in Madison, Ohio, this 30-acre, hidden gem is heavy on research and stunningly beautiful.

Started by David Leach in 1970, this satellite facility is a hub for rhododendron horticulture and research in the Midwest. A pre-eminent horticulturist, rhododendron hybridizer and authority, Dr. Leach pursued cold hardy and colorful rhododendrons for the Great Lakes region and beyond. His work saw the introduction of approximately 80 named hybrids developed at his former home in Brookville, PA, or at the Madison research station. The Leach Research Station was donated to The Holden Arboretum in 1986.

Sandy soils and a lake-moderated climate make the research station one of the best places for rhododendron cultivation in the Midwest. The station has nearly 12 acres of display areas and more than 2 acres of field growing space. The display areas are arranged as strolling gardens where more than 1400 rhododendrons are being evaluated and preserved long term. Recently, the station has taken on a wild germplasm conservation role, and more and more wild-occurring rhododendron species are being added to the display areas. The fields are used for evaluating temporary breeding populations of several thousand unique seedlings or for other field research.

We are unable to be open to the general public outside a few open days in May. However, we encourage scholars of all kinds, green industry groups, gardening groups, or any other interested parties to get in touch about visitation and facility use opportunities. Reach out to Rhododendron Collections Manager Connor Ryan ( for more information.

Explore our Collection

Browse our collections map to learn about our extensive collection of rhododendrons and other plants. We honor our commitment to David Leach by remaining closed to the public most of the year, so plan to visit on one of our spring open days!

The map allows users to filter and search the collection by attributes such as name, genus, family, etc. Get in touch about research and conservation, visitation, or other site and collection use by contacting Rhododendron Collections Manager Connor Ryan (

David G Leach Station Virtual Tour

Landscape Plant Breeding

Situation Developing tough plants for human spaces. Our Research Whether in an old growth forest or an urban street, plants benefit our physical and mental well-beings and provide countless ecosystem services. Unfortunately, not all plants are well-adapted to human spaces, or they become less-adapted as our environment changes. Our group seeks to develop new plants… »

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Rhododendron Collection Curation

Situation How can we build a Rhododendron collection to meet the needs of HF&G staff and our partners and provide an inspiring guest experience? Our Research Rhododendrons have a storied history, both locally and across the world, and they have thrilled gardeners for centuries. The genus contains roughly one thousand wild-occurring species, and man-made selections… »

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Leaf and Flower Heat Tolerance of cold hardy Rhododendron species

Question How will climate change impact Rhododendron growth, reproduction, and survival under stress? Project Summary Rhododendron is one of the most popular woody ornamentals used as landscape plants around the world. While Rhododendron are well-adapted to cold climates, owing to changes in climate, heat stress is becoming a major factor limiting Rhododendron production. The way… »

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