JARS v58n2 - The Past is Prologue: Some Lesser-Known Gable Rhododendrons

The Past is Prologue: Some Lesser-Known Gable Rhododendrons
Jane M. Goodrich
Vienna, Virginia

The Potomac Valley Chapter is undertaking a major project: it will establish a Gable grove at the John C. and Margaret K. White Horticultural Center in Fairfax County, Virginia, in honor of the hybridizer Joseph Gable. Margaret has transferred her lovely 13-acre garden to Fairfax County as a horticultural park. She already has an outstanding collection of the better known Gable rhododendron hybrids, such as 'Cadis' and 'Caroline', many over 20 feet tall.
Beginning in the 1930s, Joseph Gable, a nurseryman from Stewartstown, Pennsylvania, hybridized rhododendrons suitable for the East Coast and continued until he died in 1972. The results were outstanding. In 1973, the Potomac Valley Chapter formed the Gable Study Group to evaluate his work (1). Combining Gable's original notes with responses to a survey, the results were published in Hybrids and Hybridizers (2). Many of the plants from Gable's later crosses have since been tested and named. These lesser-known clones we will plant in Margaret's garden to complete the collection. As a surviving member of the Gable Study Group, I have suggested a number of Gable's lesser known clones - considered, yes; biased, you bet.
The winner, hands down, is 'Mount Siga' ( R. vernicosum , affinis, Rock #18139). The flowers are peachy pink. The "affinis" which Gable always attached to the label means "like the species", in this case, like R. vernicosum . Is it a vernicosum ? Probably not. The seed came from the 1929 Joseph Rock expedition to China. The name Mount Siga refers to a mountain in southwest Sichuan province of China in the region where the seed was probably collected. Don't look for it on the maps where it is spelled with a Z. Its sibling, 'Kulu', is the pinker of the two, and it is named after a city in China in the same general region. Neither plant has been hurt in the last thirty years in northern Virginia, despite some bone-dry summers and below-normal winter temperatures.

One of the R. 18139's, 'Mount Siga', was crossed with Rhododendron houlstonii (now R. fortunei ssp. discolor ) to produce "1964", the most outstanding plant to bloom that year. Caroline Gable, Joseph Gable's daughter, later named that plant 'Dr. Rock' (registered as 'Doctor Joseph Rock') after the plant explorer whose seed collections came Gable's way. It favors 'Mount Siga' in color. A sibling from that cross, 'Shell'*, favors R. houlstonii (now R. fortunei ssp. discolor ).

The Gable white Rhododendron vernicosum came from seed of Joseph Rock's 1932 expedition to northwest Yunnan. Gable called this his "true vernicosum" to distinguish it from the R. 18139's. When Gable was ill with pneumonia, Guy Nearing planted the seed for him, a testament of their long and fruitful friendship.
There was an old plant down in Gable's Woods that was long thought to be a hardy white Rhododendron decorum . One day it was discovered to have red stylar glands. These glands are small, sticky structures along the style. This meant it could not be R. decorum but placed it in the vernicosum group instead. Its seed came from the 1924 Rock expedition and its number is R. 6829. Its progeny do come true from seed.
'Anne Glass', a lovely white with a pale green throat, was named for the wife of Powell Glass. The cross is 'Catalgla' x R. decorum . 'Catalgla' is an acronym for Rhododendron catawbiense , white flowered, Glass. Powell Glass found a white R. catawbiense while fishing in a mountain stream in Virginia and sent seed from this plant to Gable.

'Mary Belle' is, of course, an outstanding plant. Its progeny with R. 18139 produced a new winner, 'James Allison'*. Its pale ivory flowers have a deep carmine throat. The medium green foliage lacks the characteristic 'Mary Belle' twist, but it reappears in the next generation. 'Vandal'* is a sibling of 'James Allison'*; Caroline Gable chose that name because someone stole all of its trusses one night.
'Mary K', an off-white, was named for Gable's daughter-in-law. It is a cross of the hardy white 'Catalgla' and Gable's hardy Rhododendron fortunei . Gable and Nearing worked for seven generations to get the hardiness in R. fortunei , seed of which came from England. 'Mary K' is hardy in New England. Watch for a pinkish sport.
'Mac Kantruss'* is named for a Gable grandson. It is a pale red with distinct red throat and blooms a bit later than mid season. One year it won Best in Show at the Potomac Valley Truss Show. The cross is Degram Group x Atrier Group. 'Hopewell'* is a sibling.
'Rhein's Find'* was selected from the plants of the cross 'Kluis Sensation' x 'Cadis'. Its charm comes from a pale red blotch set in an off-white flower.
'Peaches'* came from a selection in Gable's Woods where the results of the cross Atroflo Group x Atrier Group were planted. This is probably the correct parentage. The trusses open a clear peach color with no blue cast and it becomes a tall plant in time.
'Atroflo No. 2'* is a great red with outstanding indumented foliage. It will bloom in shade or partial shade and buds up young. There are actually three numbered Atroflo's: 'Atroflo No. 1'* got the Award of Excellence, 'Atroflo No. 2'* is the hardier, and 'Atroflo No. 3'* is sparsely available. Gable recorded the cross as 'Atrosanguineum' x R. floccigerum Rock 18469. The latter was a plant from Joseph Rock's 1929 expedition to China. Fearing his floccigerum was tender, Gable dug the plant each fall and wintered it in his barn. The parentage of Atroflo Group has come under much discussion and many opinions have been aired. 'Atroflo No. 2'* has been selfed, but we will have to wait for the results to ascertain the parentage.

'Mary Yates' was named by Henry Yates. He and Joe Gable made the cross 'Marcath'* F2. The shared seed produced for Gable the series called "Tommies,"* which included 'Bonnie'* and 'Little Bonnie'* and many clones only identified by numbers. They are bicolors and solids. Caroline Gable said this group was exceptionally brilliant pink even on cloudy days.
Plants of Rhododendron fortunei x 'Madonna' and the reverse cross, 'Madonna x R. fortunei (Madfort Group), were planted side-by-side in Gable's Woods. Both crosses produced lovely whites. Enthusiasts who bought seedlings often made cuttings and sent them back to Gable, explaining that he had sold them the best one and he should have a plant to keep. The clone that goes to Margaret's garden is R. fortunei x 'Madonna'. It buds up young.
Catmar Group ('Catalgla' x 'Mars') has several forms. They are all robust growers with large leaves and are hardy in southern Canada. The deep edging of each flower surrounds a center of marshmallow-like white. The plus: deer don't seem to like it. The minus: it's a bit hard to root.
'Nearing Pink'* is a plant hybridized by Guy Nearing who shared seed with Gable. Gable wrote of the seedlings of this cross (which bloomed in 1954), the finest of this group of hybrids from Nearing. Surprisingly, the cross is ( R. decorum x R. griffithianum ) x ( R. williamsianum x R. auklandii ). Rhododendron auklandii is the former name for R. griffithianum . Seed from both of these parents came from Mr. Magor in England. Whether the seed of both were hand pollinated or gathered open pollinated is a matter of conjecture. We do know that Nearing kept plants of 'Degriff'* (there were only six of them) in his hand dug pit. Whatever the explanation for the hardiness, 'Nearing Pink'* is a beautiful medium pink with a cherry red throat, blooming about three weeks later than 'David Gable'.
One spring a few of the Gable Study Group were in Gable's Woods with Caroline Gable. We stopped near a lovely apricot pink. The charts we had indicated the cross was Maxhaem Group x 'Caroline'. Caroline remembered that the plant 55-64 introduced as 'W. H. Ebaugh'* came from that spot, so at last there was a match for the parentage. Another clone, 56-64, is a sibling.
'Mary Garrison'* is a cross of Rhododendron vernicosum , aff. R. 18139 with a cream colored R. fortunei . The latter was found in a batch of R. fortunei seedlings. The resulting plant has a large lax truss of pinkish cream with a distinct reddish brown blotch and that blotch seems to be dominant in future generations with 'Mary Garrison'*. You have to love a lax truss or set the plant on a bank to look up into the flowers. 'Mary Garrison'* has produced some very nice progeny.
Many thanks to all those who have supplied cuttings, rooted the cuttings, and nurtured them along. As these young plants get larger, they will be moved to a permanent display area in Margaret's garden for future generations to enjoy. Special gratitude, of course, goes to Joseph Gable who hybridized all these beauties.

* Name is not registered

References
1. Gable Study Group members; George Ring III (chairman), Caroline Gable, Ray and Jane Goodrich, Russ and Velma Haag, and George Miller.
2. Livingston, Philip A., and Franklin H. West, editors. 1978. Hybrids and Hybridizers; Rhododendrons and Azaleas for Eastern North America. Harrowood Books, Newtown Square, PA.