Notes from the Hybridizers Roundtable: ARS Annual Convention, King of Prussia, PA, May 14, 2004
William Meyers II
Five well-known rhododendron hybridizers were scheduled to speak at the Sunday morning Hybridizer's Roundtable, each about their recent experience at hybridizing.
Allan Anderson discussed color pollution and his efforts to cross Western plants having interesting colors, with hardier Eastern hybrids and species. He noted that his general experience is that colors seldom hold true in these crosses. This has proven particularly true in crossing yaks (Rhododendron degronianum ssp. yakushimanum) with reds in which the reds don't often come through or they get changed completely. In his words, "Yaks do bad things to reds." He has, however, found that crosses using R. maximum do allow reds to come through. Rhododendron pseudochrysanthum will allow reds to also survive the crosses but R. pseudochrysanthum is not very hardy, particularly in the Northeast.
With regard to yellows, Allan's experience is that most crosses with R. ponticum are not very good at letting yellows through and that R. maximum will actually fade yellows as do yaks. He has found that R. aureum will let yellows survive but they seem to also pass on fungal growth in the summer heat along the East Coast. Investigating the parents of West Coast yellow hybrids that he liked, most appeared to have R. fortunei in their background. Allan added that some hybridizers are trying to use Dexter crosses to produce yellows but no conclusion has been reached yet.
In concluding, if trying for yellow hybrids, Allan suggested using crosses with R. fortunei and avoiding R. ponticum in their pedigrees. Examples that Allan feels appear to be good for the East are 'Janet Blair' x 'Yellow #1'* and 'Nancy Evans' x 'Janet Blair' (ancestry undocumented).
Werner Brack continued the discussion of yellow hybrids and showed slides of a number of his crosses, some of which he has registered. One of those that he particularly likes is 'Voluptuous' ('Scintillation' x 'Mary Belle'). Two others Werner presented were 'Janet's Fantasy' ('Apricot Fantasy' x 'Janet Blair') and 'Peach Freckles' also ('Apricot Fantasy' x 'Janet Blair). Another hybrid he's evaluating is ('Janet Blair' x 'Phipp's Yellow'). Werner uses 'Janet Blair' because it is good in deep shade and the yellow seems to come through well. 'White Elegance', a 'Janet Blair' cross, is in tissue culture now and has proven to be floriferous in deep shade.
He also finds 'Hotei' a good seed parent and pointed out that 'Nancy Evans' is a hybrid with 'Hotei' in its genealogy. Another yellow hybrid, soon to be registered, will be called 'Brookhaven' ('Hotei' x 'Janet Blair'). On the other hand, though it has pollen, "the pollen of 'Hotei' doesn't work". He pointed out that though 'Nancy Evans' is pollen sterile, it works as a female parent.
Werner believes 'Janet Blair' has R. fortunei in its background and therefore will tend to preserve color in its crosses. One of his crosses, 'Orange Leopard' ('Voluptuous' x 'Point Defiance'), is a low, compact grower with lots of orange color. Another cross of Werner's, about to be registered, is 'Brocade' ('Phipp's Yellow' x 'Janet Blair'). A hybrid that is cream with a reddish brown blotch is a cross of ('Phipp's 84'* x 'Janet Blair') and has produced large, 4-inch (10 cm) flowers.
Werner summarized noting that 'Voluptuous' produces lots of pollen and he's found it can be used as a parent in both directions.
John Doppel, of Lanarch, PA, said he lives in an exposed, area, windy in winter, open and hot in the summer. His goal has been to develop crosses that will survive in those conditions. He has found the venerable 'Roseum Elegans' works just fine. In looking for similarly hardy hybrids, John has crossed 'Peter Alan' x 'Anah Kruschke' and produced a "nice red" truss with up to 30 flowers and very little leaf burn. He also has found that 'Casanova' passes on the traits of being creamy in color with tough foliage. 'Peter Alan' tends to produce blotches in its crosses.
Hybrids with 'Blue Peter' in them appear to have leaves that do not do well in his winter conditions, but while foliage of R. fortunei crosses does all right in his winter exposure, it often burns in his summer conditions. Ed Reiley, next to whom I was sitting during the presentation, leaned over and said to me his R. fortunei crosses are in full sun and don't burn at all. (Perhaps John's exposure is more open to drying summer wind than Ed's.) John indicated a cross of 'Blue Peter' x 'White Dimples' seemed to be fine in his conditions and that R. dicroanthum and 'Whitney's Orange' both seem to stand the sun and heat in John's environment.
Dick Gustafson spoke about hardiness. He frequently uses 'Party Pink', a Leach hybrid, for hardiness in his crosses. Dick has also found 'Hachmann's Brasilia', a not particularly hardy German hybrid, when crossed with 'Red Peach' produced a "reasonable" hybrid. He also liked the results of 'Janet Blair' x 'Hindustan'. Dick's experience is that crossing yellows with 'Janet Blair' will produce pale yellow hybrids. He has been using 'September Song' frequently, which has a loose, mostly orange, multicolor truss. Its crosses produce interesting colors but he is still trying for a tighter truss.
Dick has also been using 'Eleanor Hotchkiss'* and 'Dorothy Russell', both for their large trusses, to try to maintain that characteristic. He has crossed 'Todmorden' x 'Swen', both bi-colors, to try to produce a less rangy hybrid than 'Todmorden' itself. He has also found 'Orange Honey' to be very pretty and super hardy.
The last scheduled speaker was one of our two new Gold Medal recipients, Jim Barlup, who had given a super presentation the previous Friday night of some of his current hybridizing activity. At the Roundtable, Jim further discussed his efforts in making East-West crosses. He has found 'Lem's Cameo' to be not very hardy and therefore it tends to produce crosses which are also not very hardy. He has also found 'Nancy Evans' to not be very hardy but the color is good so he feels it would probably make sense for it to be further crossed to attempt to gain the desired hardiness. Jim seemed to like 'Recital' as a hardy yellow. He's also found 'Ingrid Mehlquist' durable to –25°F (-32°C); however, his experience is that its seed does not germinate very well.
Jim has crossed 'Nancy Evans' x 'Helsinki University' and produced "a very pretty hybrid." At the same time he explained a cross of 'Nancy Evans' x 'Capistrano' produced no pollen. The cross of 'Golden Gala' x 'Summer Peach' bloomed in June for Jim and 'Glenna' x 'Janet Blair' developed a yellow hybrid. Jim found too, that 'Janet Blair' crosses tend to produce better yellows for him and seem to be good to –15°F (-26°C). An example is a cross of 'Amber Touch' x 'Janet Blair' which produced a nice and strong yellow truss. His cross of 'Horizon Lakeside' x 'Arctic Gold' also let the yellow come through and appears to be hardy. 'Nancy Evans' x 'Tweety Bird'* ('Bambi' x [R. degronianum ssp. yakushimanum x R. proteoides]) produced a strong yellow in a hardy and low growing plant.
Following the above presentations and slide shows, many of those assembled started to get up to leave, although there was still about an hour left in the allotted time for the Roundtable. Joe Parks spoke up, suggesting that "while we had seen a lot of pretty pictures and heard from some experienced and well qualified hybridizers, that wasn't the real purpose of the Roundtable. It was his point of view that the assembly of experts, and others, should be talking about significant issues relative to hybridizing and to the ARS and should be pooling their experience, information and research about certain areas of interest. One such subject he suggested as being timely, and of major import, is that of disease resistance. Joe asked if anyone had comments about that, or other matters, for discussion in the time remaining. To start things off, he gave examples of hybrids he has found to be disease resistant which included 'Disca', 'Cadis' and 'Caroline'. Bud Gehnrich added that he has found R. fortunei and 'Ingrid Mehlquist' to be phytophthera resistant. Joe made the point that if rhododendrons are to survive the next 100 years, it's important to deal with this type of issue, and other "critical matters," now.
There was some suggestion that this type of subject would be good for an Internet discussion. Another mentioned that the International Rhododendron Register would be a good place to record this type of data and that, by doing so, the information would become available internationally. The Register has over 20,000 names in it now. Databases could be developed which are completely searchable, so that one could ask for plants that are, as examples, phytophthera or mildew resistant, and obtain a print-out of hybrids and cultivars that meet those criteria. It was mentioned that just because a plant doesn't die of phytophthera, it doesn't mean it's phytophthera resistant. Another member suggested applying for a grant to undertake a study. Joe queried, "While a study is probably a good idea, who's going to do it? Most of us are amateurs."
Karel Bernady indicated that some German hybridizers have performed an investigation to try to determine the best rootstock to use for grafting relative to disease resistance. Another comment made was the need to look at insect damage such as that caused by the black vine weevil, as well as at other diseases and petal blight. Bud Gehnrich reminded the audience that one could obtain a grant of up to $5,000 from the ARS Research Foundation to do real research on one such issue at a time. Joe Parks mentioned that he had done some research on azaleas but not on rhododendrons.
It was mentioned that the RHS has completed its review of the International Rhododendron Register and will be publishing the enlarged and revised version shortly. Jay Murray, North American Registrar of genus Rhododendron names, and her husband, Bob, have developed a proprietary database of rhododendron and azalea information over a period of almost twenty years, at a cost of more than $25,000 for equipment and software. The database, which includes all registered plant names and descriptions, as well as available data on unregistered plants, is fully searchable. Information about disease resistance, for example, may be extracted from the records readily. It is necessary, however, that the information be made available to the Murrays so that they may include it. Reasonable requests for information are welcome.
Clay Starke, a major West Coast nurseryman and a member of the Tualatin Valley Chapter, stated that he hadn't heard much about shipping and diseases. Sudden Oak Death (phytophthera ramorum) is now a major potential problem that can wipe out all rhododendrons and, because it's airborne, dealing with it is a current, major cause of concern for him and for most of the West Coast nurseries and should be for all of us. It was stated that extension agents can test for S.O.D. and many are working on the problem now.
Clay challenged someone in the audience to go beyond just talking, to take on the research about which many spoke and to set some specific goals and dates to get it accomplished. Joe Parks was the only one who stepped up and said he would contact the Massachusetts Chapter to see if anyone in that chapter would agree to help with research on disease resistance. No one else at the session volunteered to "pick up the gauntlet." Hopefully a reader will. Interested volunteers should contact Joe Parks. The sooner, the better!
Just before adjourning, Al Fitzburgh suggested that someone record the Hybridizer's Roundtable and discussions, as apparently had been done in previous years. Those minutes were then published in our ARS Journal. Being an interested neophyte, I had taken a lot of notes and volunteered afterward to our editor, Sonja Nelson, that I'd send her my notes if she'd be willing to edit them, as she does so well, if she thought them fit for publication. Hopefully I got most of the issues, names, hybrids and cultivars correct, as well as the sense of the discussions. If not, I hope you'll be forgiving. Please let me know of any corrections and I'll pass them on to Sonja for notation in a future issue.
* Name is unregistered.
Bill Meyers is president of the Mason Dixon Chapter.