Rhododendron Cultivars Y

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New article for Trees and Shrubs Online.

Recommended citation
'Rhododendron Cultivars Y' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-cultivars-y/). Accessed 2026-01-19.

Family

  • Ericaceae

Genus

Other taxa in genus

Glossary

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Credits

New article for Trees and Shrubs Online.

Recommended citation
'Rhododendron Cultivars Y' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-cultivars-y/). Accessed 2026-01-19.

Editorial Note

Entries here are derived, unchanged, from Bean’s articles on Rhododendron hybrids, which, as transcribed into Trees and Shrubs Online format, were unsearchable. These entries, from his sections on “Rhododendron hybrids”, “Deciduous azaleas” and “Evergreen azaleas”, have been extracted and given their own entry under a series of pages Rhododendron Cultivars A, B, etc. Each cultivar’s affiliation to the above categories is noted.

Hybrid rhododendrons follow an unconventional form of nomenclature. All progeny of a stated cross form what was formerly called a grex, now called a Group, and share the same grex/Group name, which is not given inverted commas. For example, all progeny from the cross R. decorum subsp. diaprepes × R. auriculatum are in the Polar Bear Group, and all from any cross between Rhododendron Aurora Group and Rhododendron griffithianum are referred to Yvonne Group, regardless of when or by whom the cross was made. Within the Group individual clones may be recognised as cultivars, being identified by the use of single inverted commas in the usual way: Rhododendron Polar Bear Group ‘Polar Bear’, or Rhododendron Yvonne Group ’ Yvonne Pride’. Reference to the the International Rhododendron Register and Checklist, produced by the Royal Horticultural Society, is advised. A digital version is available through the good offices of the RHS Rhododendron, Camellia and Magnolia Group.

The cultivars presented here represent a fraction of the total diversity of Rhododendron cultivars, comprehensively covered by the Register. The listing on TSO will be developed further when funding permits.


Yellow Hammer (flavidum × sulfureum)

Lepidote rhododendron

Flowers from terminal and upper axillary buds, mostly in pairs from each bud. Corolla tubular-campanulate, about 7⁄8 in. long and 3⁄4 in. wide, downy on the outside, soft yellow. Leaves about 11⁄2 by 1⁄2 in., darkish green, scaly beneath. Moderately dwarf, to 5 or 6 ft, taller in woodland. March or April, but a fair proportion of the flower-buds opening in autumn. A very popular hybrid, raised by J. C. Williams of Caerhays Castle, Cornwall, before 1931.


'Youthful Sin'

E. J. P. Magor also crossed R. cinnabarinum with R. yunnanense (Yunncinn grex). He judged the result to be inferior to Oreocinn, but the Yunncinn cross was repeated at Bodnant and produced the clone ‘Youthful Sin’, which received an Award of Merit in 1960.


Yvonne ('Aurora' × griffithianum)

Elepidote rhododendron

Flowers about 11 in the truss; rachis 21⁄2 in. long. Corolla widely funnel-campanulate, about 4 in. across, pink in the bud, opening ivory-white with a pink flush. Style with a large green stigma. Calyx green, shallowly and obscurely lobed. Leaves 6 in. long, half as wide. (Rothschild.) The description is of ‘Yvonne Opaline’, which was the first to be exhibited, and received an A.M. in 1931.


'Yvonne Pride'

Elepidote rhododendron

In ‘Yvonne Pride’ the flowers are creamy white with a red eye (A.M. 1948). The Yvonne cross is related to Loderi, but with an infusion of R. thomsonii through ‘Aurora’. The only other species involved is R.fortunei. The plants need a sheltered position and flower in late April or early May.