Some Notes on Rhododendron Breeding in the Eastern United States
John C. Wister, Swarthmore, Pa.
Based on a talk given to the New Jersey Chapter, October 21, 1964
In 1961 I presented at the International Rhododendron Conference in Portland a paper on the pioneer breeding work of Joseph B. Gable, Guy C. Nearing and the late Charles O. Dexter.
In this paper (later printed in the Proceedings of the Conference) I traced the beginnings of rhododendron growing with the Anthony Waterer hybrids produced in England in the first half of the 19th Century and brought to this country in 1876. These are still widely grown here under the general name of "Iron-Clods" or "Catawbiense Iron-Clads." They are still valuable here because of their hardiness, but they have long since been pushed into the discard in Great Britain and on our West Coast, by the hundreds of the new hybrids of the past thirty or forty years which have far finer flowers.
Some of the expert rhododendron growers of New Jersey, Long Island and Southeastern Pennsylvania grow some of these improved varieties, among them, to name a few off hand, 'Cynthia', 'Mars', 'Mrs. Furnival', and 'Vulcan'. But by and large these magnificent hybrids now being introduced by breeders on our West Coast, do not like the climatic conditions in the East and are not satisfactory in most gardens. They like mild winters, foggy atmosphere and cool summers. Many are bud tender at zero or near zero and plant tender below zero. They do not like 80, 90 or 100 degree temperature in summer accompanied by drying winds. In other words they just don't like us. We ought to recognize that, wish them well where they grow well, and go on our way to produce equally handsome varieties that will do as well here as the famous "Iron-Clads."
Three Pioneer Breeders
At Portland I told about the beginnings made by our three great pioneer breeders to give us the new varieties we want. I want to mention these beginnings briefly to give a kind of running start to my story of the newer breeders they have inspired and who are introducing or about to introduce new seedlings.
Mr. Gable's first interest when he got back from World War I was in Azaleas. I shall not discuss these here but shall confine myself to the true rhododendrons. Very shortly after 1920 he began crossing these true rhododendrons. His first introductions were lepidote hybrids such as 'Codorus', 'Conestoga', 'Conewago' etc. Then a little later came 'Caroline', 'Annie Dalton', 'Atroflo', 'Beaufort', 'Cadis', 'County of York' (Catalode), 'David Gable', 'Disco', 'Kentucky Cardinal', 'Mary Belle', 'Milo', 'Pink Twins', 'Redhead, 'Robert Allison', and others. These now being grown by quite a number of Rhododendron Society members from Massachusetts to Virginia, but they are not yet being grown in quantity for the wholesale rhododendron trade. They will, in the years to come, get this final acid test, along with dozens of others, now growing at Stewartstown but not yet propagated even in small quantities. In my opinion they form the very backbone of the future development of rhododendrons as suitable for our climate as "Iron-Clads" and surpassing them in perfection of flower and in purity of color.
It is hard to pin Mr. Nearing down to the exact date he began rhododendron breeding. His first introductions, like Gable's were lepidotes. They were produced while he was at Guyencourt, Delaware and the varieties of the R. pubescens x R. keiskei group bear the group name of Guyencourt Hybrids. The individual clones were given geographical or "place" names from the surrounding countryside 'Brandywine', 'Chesapeake', 'Delaware', 'Hockessin', 'Lenape', and 'Montchanin'. They are valuable additions in a new field of rather dwarf plants with small foliage.
From 1935-1945 Mr. Nearing continued his breeding at Ridgewood, New Jersey, crossing R. decorum and R. griffithianum with some of the hardiest red "Iron-Clods." Then after ten years most of his plants were lost in a flash flood. A few survived, among them those now named 'Beatrice Pierce' 'Gretchen', 'Nearing Purple' and 'Rochelle'. They have been disseminated in only a very small way, another proof of the many many years needed to breed and flower a new Rhododendron seedling and then propagate enough plants to put it on the market.
After the disastrous flood Mr. Nearing moved to Ramsey, New Jersey and continued testing many species for hardiness under his conditions. Of the many hundreds of crosses made and the many many thousands of seedlings produced and tested only a very few have been named and sent out to the few Rhododendron Society members enterprising enough (and patient enough!) to get on his waiting lists. Among these can be mentioned 'Mary Fleming', 'Windbeam', 'Wyanokie', 'Ramapo', 'Ramsey Tinsel', and 'Catania'.
I wish the Rhododendron Society could send a competent biographer to live with Gable and Nearing long enough to worm out of them the complete story of their rhododendron growing and rhododendron breeding during these last forty years. Both men are entirely too modest about themselves and their achievements to volunteer information.
C. O. Dexter
Much more has been written, these last years, about the Dexter seedlings than about the Gable and Nearing seedlings. Mr. Dexter produced seedlings in the twenty years 1923 to his death in 1943 under totally different circumstances. Instead of inland situations with cold winters and hot dry summers he enjoyed the comparatively mild moist sea coast climate of Cape Cod. Instead of a small place he had a big one. Instead of starting from scratch without outside help he had the advice of Paul Frost, a landscape architect who was a great Rhododendron enthusiast and who procured his foundation stock and supervised its planting. He employed competent men to prick out the yearly thousands of seedlings, plant them from flats to frames, from frames to nurseries and from nurseries to permanent positions. The beauty of his landscape plantings soon brought to him important horticultural visitors. Little by little he began to distribute propagations of some of his choicest things. Later on he gave away or sold hundreds and even thousands of small un-bloomed seedlings.
Although not publicly offered for sale in his lifetime, it was inevitable that almost immediately after his death "Dexter Seedlings" began to be offered by a number of nurseries. Like any group of hybrid seedlings they were good, bad and indifferent (particularly the last named). Rhododendron fanciers who had known Mr. Dexter and admired his work began to fear that his reputation would be ruined by the distribution of quite ordinary, if not inferior sorts.
In the late 1940's, Dr. Clement Bowers formed a small informal group or committee of five Rhododendron Society members to visit gardens where Dexter seedlings were being grown. In the years following, this group, soon increased to over a dozen members, visited more than two dozen gardens where Dexter seedlings were being grown in quantity. In each garden they voted on the best half dozen or dozen outstanding things and labeled them with code numbers.
With the gracious permission of many owners, cuttings were taken and rooted by Paul Vossberg of Westbury, Long Island and turned over to the Scott Foundation, at Swarthmore College to be grown on and tested. Later on Swarthmore surplus plants were sent to the Arnold Arboretum, the National Arboretum, and Planting Fields Arboretum, and cuttings supplied to various nurserymen and Rhododendron Society members.
Over a hundred of these selected forms have now been quite widely tested. Over a dozen have been named and offered by and distributed from a number of nurseries. Among these may be mentioned 'Amethyst', 'Champagne', 'Dexter Pink', 'Gloxineum', 'Mrs. W. R. Coe', 'Scintillation', 'Skyglow', 'Tom Everitt', 'Warwick', 'Westbury', and 'Wissahickon'. They are all beautiful. They can be recommended to Eastern rhododendron growers without any hesitation. Some are being tried on the Pacific Coast but it seems unlikely that they will be important in the areas where the more tender British hybrids flourish.
In addition about three dozen varieties have seemed promising enough to be given names. Just how many of them will be offered for sale (in the near future at least) is not clear. Among those I have liked best have been 'Betty Hume', 'Brown Eyes', 'Fordham', 'Halesite', 'Huntington', 'Josephine Everitt', 'Lavender Princess' and 'Parker Pink'.
And More To Come
At the present time, in addition to these two groups of varieties given permanent or tentative names, nearly 400 clones, selected from masses of Dexter seedlings in twenty-five different gardens, are being grown under code numbers in a dozen or more places. It is obvious that even if they all turn out to be good (which is not likely) they cannot all be distinct enough from each other to warrant growing them. I do hope however, that there may be put into the nursery trade during the next five or ten years at least 25 and maybe 50 or more varieties that our Eastern gardeners can then buy with some confidence and enjoy them in their gardens.
This long introduction to the work of the three pioneers, Gable, Nearing and Dexter brings us to the newer breeders that these men have inspired. I can at this time mention only a few of them.
Edmond Amateis who now lives in Clermont, Florida made many rhododendron crosses when he lived in Brewster, New York. This year his variety 'Dora Amateis', a cross of R. carolinianum x R. ciliatum was introduced into commerce. It is a dwarf growing variety with small leaves and white flowers. It bloomed freely at the Tyler Arboretum in Lima, Pa., this past spring and was greatly admired by the visitors to our annual "Open House."
Paul Bosley, nurseryman of Mentor, Ohio, in addition to naming and introducing several outstanding and particularly hardy Dexter seedlings, has this past year introduced 'Lemon Ice' one of his own seedlings.
Dr. Clement G. Bowers
Dr. Clement G. Bowers is a native of Maine, New York, a small community in the cold pocket of the Chenango Valley near Binghamton. This is one of the worst possible locations in which to try to grow rhododendrons but when Dr. Bowers was studying genetics and plant breeding under Dr. A. B. Stout at the New York Botanical Garden over 30 years ago his chief interest became rhododendrons. He worked with them at Hicks Nursery in Westbury, Long Island. He secured from England pollen of a number of tender species to cross on our hardy native species, including R. maximum .
By the time the seedlings bloomed Dr. Bowers was engrossed in war work and could not give them the close attention they deserved. They did not, at first, seem worthy of naming and introducing and he was too busy to consider using them for further breeding. As nursery conditions were difficult, Mr. Hicks sold a dozen or more of the plants without identification as to their parentages to Judge Collins, a nearby rhododendron enthusiast. After Judge Collins death some ten years ago, Mrs. Collins gave the plants to the Planting Fields Arboretum where they are now growing. The plants are now 6 to 8 feet or more high and across and have attracted attention because of their very late blooming. While they are not so spectacular as the finest midseason varieties a number of them do seem worthy of naming and introducing because they extend the season of bloom when nearly all other rhododendrons are over. I think they may prove of great value for further breeding.
I am glad to report that Dr. Bowers' interest in these plants has been revived and that he is trying to make arrangements to have some of them propagated and made available to both Arboretums and interested Rhododendron Society breeders. I hope that a number of the eastern chapters of the Society will lend their aid to make young plants available in the next few years.
At the time of the official dedication of the Planting Fields Arboretum in 1962, Dr. Bowers searched out and found a set of seedlings from crosses he had made over fifteen years ago when he had secured from England pollen of the tender species R. elliottii . He apparently had not seen them in bloom before and was much pleased with the particularly clear red colors. I hope propagations may be made from them or that Dr. Bowers will use them for further breeding.
Joseph Casadevall of Whippany, New Jersey, a former president of the New Jersey Chapter, has been breeding Rhododendrons for ten or fifteen years and has many interesting new seedlings. As far as I know none have been named or propagated in any quantity but some certainly will be before long. The ones that have interested me the most are hybrids of R. mucronulatum that inherit the earliness of this species and give a range of colors from white to various shades of pink.
John C. Cowles
John C. Cowles, present propagator at the former Dexter estate in Sandwich, Massachusetts, has for several years been making selections of the Dexter plants still growing there. A number of these have been named and exhibited at Rhododendron Society shows. Of these I have seen, the most unusual is 'Brandygreen'. Mr. Cowles has also grown vast quantities of seedlings from the Dexter plants and more recently has been getting pollen from Rhododendron Society members and from abroad to use in further crossing.
David G. Leach
David G. Leach lives in Brookville, the area called "the ice box of Pennsylvania" where the thermometer drops to 20 and 30 below zero. Here he has been doing the most carefully thought out breeding with the primary purpose of getting varieties definitely hardy under his conditions. The seedlings I have seen at Brookville have a great range of color, size and season and will, I am sure, be eagerly tried by rhododendron growers, amateur and professional alike when they are finally introduced.
Mr. Leach has designated three nurseries to propagate these and grow them on for introduction in 1966 or later. The following are some of the varieties that have been named, registered and/or published and described, 'Betty Breene', 'Blaze', 'Boule de Rose', 'Duet', 'Great Lakes', 'Janet Blair', 'Limelight', 'Pink Flourish', 'Spring Frolic', 'Tahiti' and 'Vernus'.
Howard Phipps of Westbury, Long Island planted great numbers of seedlings from Mr. Dexter in the 1930's. When these bloomed he began to make crosses of his own. He crossed the Dexter seedling (that has now been introduced as 'Westbury') with Paul Vossberg's variety 'Meadowbrook', and he produced two outstanding varieties which were later selected by Dr. Bowers Committee and named 'Brookville' and 'Wheatley'.
Mr. Phipps has continued his work in crossing and has at present over 5000 seedlings three and four feet high. When I saw them a year ago they made a magnificent sight. I hope a dozen or more of them will soon be selected and named and propagated to be made available to rhododendron growers.
Antonio Shammarello, nurseryman of South Euclid, Ohio, set out twenty or thirty years ago to breed early flowering rhododendrons hardy in his cold climate. Among the varieties he chose for parents were 'Cunningham White' and 'Boule de Neige'. Many rhododendron growers who have visited his nursery in the past ten years have given high praise to the many varieties which Mr. Shammarello selected from the untold thousands of seedlings from his early crosses.
It is only a few years now since some of his varieties were named and put on the market but they are already being widely grown and widely praised. A few of them have been criticized because in milder climates they tend to open their flower buds in autumn.
The Scott Foundation and the Tyler Arboretum were allowed to have test plants before their general distribution. The following have bloomed well for us there the past three or four years: 'Belle Heller', 'Cheer', 'Elie', 'Euclid', 'Holden', 'King Tut', 'Lavender Queen', 'Pink Cameo', 'Pink Satin', 'Rocket', 'Spring Dawn', 'The General' and 'Tony'.
Dr. Henry T. Skinner
When Dr. Henry T. Skinner, Director of the National Arboretum was at Cornell some twenty years ago he was more interested in azaleas than in the true rhododendrons. He did however grow some thousands of seedlings of R. mucronulatum from which he selected the one now introduced under the name of 'Cornell Pink'. It is a most important acquisition to the early blooming rhododendrons.
Paul Vossberg of the Westbury Rose Company got his early training at the Hicks Nursery and while there, or very shortly after leaving, made some crosses from which he selected the varieties 'Meadowbrook' and 'Roslyn'. They were introduced years ago and have been quite widely sold without stirring up the enthusiasm which I feel they richly deserve. I hope many Rhododendron Society members will seek out these two varieties and give them important positions in their gardens for I feel quite sure that they will earn their rightful place among our best "Iron-Clad" varieties.
Mr. Vossberg was one of the early members of Dr. Bower's Dexter Rhododendron Committee. For fifteen years I have watched his careful appraisal of the Dexter varieties that he finally named and introduced. Now he is giving the same careful study to hundreds of seedlings of blooming age which he has grown from his own carefully planned crosses. I feel sure that a number of these will soon be named and introduced.
Other Breeders to be Heard From
I have mentioned breeders whose plants I have grown at Swarthmore and Lima, or that I have seen in other gardens from Massachusetts to the District of Columbia and west to Ohio. There are other Eastern breeders whose plants I have not seen or who have not yet named or introduced their varieties. From reports that have come to me I believe that they will be heard from before too many years. I apologize for not being able to mention them all here, I urge each Chapter of the Rhododendron Society to seek them out and help them with their work in order to encourage the production of fine new rhododendrons particularly suited to each rhododendron area.