Rhododendron 'Blue Baron', which is a Mezitt hybrid documented as ['Starry Night' ('Gletschernacht') x 'Waltham'], has been determined to be a tetraploid using flow cytometry by
Dr. João Loureiro, Dr. Silvia Castro, José Cerca Oliveira, 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.
Some question whether Rhododendron 'Blue Baron' has Rhododendron 'Waltham' as the pollen parent.
Summary of Ploidy Levels
Triploid 'April Rhapsody',
Triploid 'Bluenose',
Triploid 'Purple Gem',
Tetraploid 'Blue Baron',
Tetraploid 'Blue Ridge',
Tetraploid 'Epoch',
Tetraploid 'Epoch' X Rhododendron augustinii,
Tetraploid "Medium Blue",
Tetraploid Rhododendron augustinii
Source: RareFind Nursery
John and Sally Perkins
