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Hybridizing with Rhododendron occidentale

True to human nature, the discovery of exquisite beauty in the wild did not satisfy all plant people. Some - including some of the explorers - attempted to create their own masterpieces through hybridizing.

Hybridizing with Rhododendron occidentale began in England, far from its native homeland. William Lobb imported it for the Veitch Nursery in 1850, and from this source Anthony Waterer of Knap Hill crossed it with R. molle resulting in the cross ‘Albicans’ with fragrant white flowers and a yellow blotch.

Lionel de Rothschild subsequently used ‘Albicans’ to introduce R. occidentale to his Exbury azaleas, a subgroup of the Knap Hill azaleas developed by Waterer. He was attracted to the “square-faced,” wide petals of the flowers. In spite of the supposedly “inferior” population from which Lobb obtained seed, the species contributed to the great success of the Exbury azaleas, especially their fragrance. Koster & Sons of Holland also used crosses with R. occidentale in its hybridizing, producing among others ‘Delicatissimum’, ‘Graciosum’ and ‘Irene Koster’.

In the mid 1900s back in America, Leonard Frisbie of Tacoma, Washington, began crossing R. occidentale with other species, producing among others ‘July Charm’, a cross of R. prunifolium with his R. occidentale selection ‘Coquille’. Ben Lancaster of Camas, Washington, produced the Lackamas hybrids using R. occidentale crosses with the Ghent hybrids. Among his results are ‘Kalama’ and ‘Wallowa’.

Unable to find a yellow-flowered R. occidentale in the wild, veteran plant explorers Britt Smith and Frank Mossman decided to help nature along. In the 1960s, they crossed two selections of the species with yellow in the blotch area and some yellow on the petals. They successfully produced a plant with yellow on the petals extending out to narrow white margins.

Today, hybridizing efforts continue apace. Mike Creel of Lexington, South Carolina, one of the few East Coast hybridizers - perhaps the only one - is crossing R. occidentale with the eastern native R. flammeum. And Richard Cavender of Sherwood, Oregon, may have the most ambitious hybridizing program, with goals of double frilly flowers that bloom in July through September and that are resistant to powdery mildew. He uses a cross of two “good red” R. cumberlandense (formerly R. bakeri) with R. occidentale, resulting in flowering from late May through mid June, some with fragrance and mildew resistance and with double pink flowers.

by Sonja Nelson