Tyler Arboretum

Rhododendron Collection

Tyler Arboretum
Media, Pennsylvania
Richard A. Colbert, Executive Director
Carla Hetzel, Plant Curator

Primary Focus:
Collection represents broad taxonomic diversity including cultivars

529 taxa, 1493 accessions, 100% from cultivated sources
Includes -
27 Rhododendron species, varieties, and selections
113 Rhododendron cultivars
25 Azalea species
131 Azalea cultivars
76 Dexter Hybrids
157 Swarthmore Hybrids

The Wister Rhododendron Garden is one of the largest collections of hardy elepidote rhododendrons in North America. Initiated in 1953, the collection represents the culmination of a life's work by one of the leading rhododendron breeders in the United States, Dr. John Casper Wister. Wister amassed representative hybrids of major breeders, including Dexter, Gable, Leach, Nearing, Skinner, and Glenn Dale. Very hardy hybrids developed in the 19th century termed "Ironclads" were included, as well as Swarthmore hybrids from Scott Arboretum nearby on the campus of Swarthmore College. Wister selected for late-blooming, increased hardiness, improved flower color and fragrance. Primarily featuring named rhododendron cultivars and un-named hybrids, the collection today is a remarkable assemblage of large-leaved evergreen rhododendrons suitable to growing conditions of the Mid-Atlantic region of the United States. Plans for the collection include propagation of unique or rare taxa, and added educational components to tell the story of this historical rhododendron breeding program.

Taxonomic References and Authorities:
The International Rhododendron Register and Checklist, 2nd edition, The Royal Horticultural Society, 2004.
Azaleas, revised and enlarged edition, Fred C. Galle, Timber Press, 1991.
Manual of Cultivated Broadleaf Trees & Shrubs, 3 vols, G. Krussman, 1985.

June 2006