Rhododendron 'Betty Wormald', which is a 1907 Koster hybrid documented as a 'George Hardy' hybrid, has been determined to be a triploid using flow cytometry by
Dr. João Loureiro, Dr. Silvia Castro, José Cerca, and Mariana Castro
Plant Ecology and Evolution Group,
Centre for Functional Ecology,
Department of Life Sciences,
Faculty of Science and Technology,
University of Coimbra, Portugal.
Rhododendron 'Betty Wormald' is documented as the seed parent of 'Scandinavia'.
Summary of Ploidy Levels
Triploid 'Betty Wormald'
Source: Van Veen Nursery
John and Sally Perkins
