KALMIA LATIFOLIA SELECTIONS AND THEIR PROPAGATION
ANNUAL SHOW RETURNS TO FIELD STATION
PERSONAL OBSERVATIONS THE DEXTER RHODODENDRONS
PERSONAL HISTORY OF THE DEXTER RHODODENDRONS
ROBIN HILL AZALEAS
HARDENING OFF RHODODENDRONS AND AZALEAS
A VISIT TO EXBURY ANNUAL SHOW AND AUCTION
Kalmia latifolia, Selections and Their
BY ALFRED J. FORDHAM, HOPKINTON, MASS.
Consultant, Weston Nurseries
While at the Arnold Arboretum I worked on the propagation of Kalmia latifolia and have prepared a table showing the outcome of that effort. It gives data concerning 29 experiences, most of which show a high degree of success.
Through the years many cultivars of Kalmia latifolia (Mountain Laurel) have been selected as natural variants either in the wild or from nursery rows. Oddly enough, K. latifolia 'Rubra', one of the first cultivars of this native American plant to appear in the records of the Arnold Arboretum, came from the English nursery firm of Veitch and Son in 1886. From native sources, the Arboretum received such Kalmia latifolia cultivars as 'Obtusata' (1886), 'polypetala'(1870), and 'Myrtifolia' (1885).
Despite the fact that good garden forms were first described about a century ago, few were carried in nursery lists. This can be explained by the fact that they were previously considered difficult to propagate from cuttings and percentage of success was small when they were grafted.
In the early 1940's, Edmund Mezitt of Weston Nurseries became interested in mountain laurel selections, particularly those with deep red buds, pink flowers, etc. Plants with similar characteristics were planted side by side to insure cross pollination. The resultant seeds were sown and plants were grown on for further select ion. This program led to some spectacular clones. I am now associated with Weston Nurseries as a consultant and one of my involvements is an effort to get these into commerce. By using the procedures described below the project is now underway.
Much of the mountain laurel propagation herein described was carried out in polyethylene chambers which have some distinct advantages. Nutrients do not leach from the cuttings as can happen when cuttings which root slowly. are placed under mist. The chambers are carefree and can be left for long periods of time without attention. There is little chance of loss through human or mechanical failure. Many taxa normally considered difficult can be rooted in high percentages.
The chambers were constructed on benches with side walls about 5 high. They were first lined with 2 nil polyethylene film. Bottom heat was provided by heating cables, so about 1 inch of medium was placed in the bench and cables installed at that level. To disperse the heat more evenly, j inch galvanized hardware cloth was placed in contact with the cable. The bench was then filled with medium consisting of equal parts horticultural grade Perlite and sphagnum moss. Welded joint wire of 2 by 4 mesh was shaped to form supporting frames which held the 2 mil plastic covering about 8 or 10 inches above the rooting medium. Bottom heat was maintained at about 75 degrees F
The "quickdip" preparations are diluted from concentrated solutions while the 2,4,5 TP formulations are in talc. Mountain laurel cuttings are made from current year's growth and can be taken as soon as the growth ripens. The stems are cut to a uniform length, (any leaves that would be below the rooting medium are removed) and they are wounded so that they will produce well distributed root systems. This is accomplished by slicing two slivers of rind downward for a distance of 1 to 1 1/2 inches on opposite sides at the base of the cutting. This procedure removes physical barriers to root emergence and exposes more surface to the action of root inducing substances. Wounding both sides of the cutting is important to prevent a lopsided root ball. Mountain laurel roots slowly, taking from 4 to C months.
ROOT INDUCING MATERIALS
Some of the most effective treatments in our experiences were 5-second dips using IBA plus NAA at various strengths or treatment with 2,4,5, TP powder formulations. Because of clonal variation, there were instances where IBA plus NAA was superior, while in other cases, 2,4,5, TP proved better. In the course of our current work at Weston Nurseries, a number of formulations are being tested. When sufficient propagating wood is available, we use as many as eight treatments. The treatments proving most effective, however, are 2,4,5 TP at 1,000 parts per million or IBA plus NAA at 2500 parts per million each.
We are grateful to the Research Department, Agricultural Chemicals Division, Amchem Products, Inc., Ambler, Pa. for providing the experimental materials being used.
PROPAGATION FROM SEED
The five-chambered, globe-shaped seed capsules of mountain laurel ripen in autumn and later split to release their seeds. Seed examined in December shows some but not all, capsules open at their tops. Nature's design prevents spilling of the minute seeds, yet allows high winds to whip them out and carry them away from the mother plant A dispersal adaptation such as this leads to wide latitude in collection time and one can expect to find some seeds remaining in the capsules throughout the winter.
Most very small seeds do not have benefit from pretreatment by cold; mountain laurel, however, is an exception. Germination of 20 to 50 % can be obtained without stratification but it is increased and unified if its seeds are subjected to a cold treatment. This can be accomplished by sowing the seeds in pots or other containers and placing them out-of-doors for the winter in a sheltered location such as a cold-frame. An alternate method of stratification would be to put the containers of sown seed in a polyethylene plastic bag which is bound at the mouth with a rubber band to make it vapor-proof. The cold requirement is then satisfied by putting the bag in a household refrigerator for three months.
MOUNTAIN LAUREL SELECTIONS
In the Boston area, mountain laurel blooms about June 1st and its course of flowering is longer than that of most woody plants. The span between bud opening and flower drop covers about 3 weeks. Flowers of red budded forms and those with banded corollas tend to flower later and to persist for greater periods. At Weston Nurseries, there are several blocks of mountain laurel from which selections are made. Those thought to have merit are moved to particular areas where they can undergo further observation. In order that evaluations be uniform, only one person is involved in making judgments. During the last few years R. Wayne Mezitt has undertaken this endeavor.
IMPORTANCE OF CHARACTERISTICS OTHER THAN FLOWERS
In seedling populations of mount am laurel, one finds plants with varying characteristics. Some with special horticultural merit display bright red, yellow or orange stems which on many plants are contrasted against dark-green leaves. One particularly striking specimen at Weston Nurseries is characterized by compact growth habit, red stems and dark green leaves with-' red mid-ribs. Some of these beautiful features are prominent throughout the year and therefore should receive consideration when selections are being made. The plants described here were grown in full sun. Were they grown in shade or partial shade their coloration might not be so intense.
Annual Show Returns to Field Station
The 1978 edition of the annual show and auction of the
Massachusetts Chapter took place May 28, 1978 at the University
of Massachusetts Experimental Station at Waltham, with its fine
facilities and geographic location.
In spite of an extraordinary adverse spring which raised havoc with blooming patterns, over three hundred exhibits were in competition with an excellent representation of both rhododendron and azalea.
In addition a beautiful table of Tony Consolini hybrids were provided by Mr. and Mrs. Harold Pilkington of Monument Beach.
Following the show Louis Cook capped the day by auctioning over three hundred plants, about fifty of which were from the West Coast.
Judges: Gus Kelley Bob King, John Gwynne, Gus Carlson, Jon Shaw, Chas. Gredler, Peg Lawson, Maurice Hall, Dick Leonard
Clerks: Mrs. Charles Eaton Bertha Atwater Joy Marlenson
TROPHY AND BLUE RIBBON AWARDS
Best in Show: Louis Cook Trophy-Mars x yak, Willard Hunnewell
Best Hybrid: Weston Nursery Trophy-Cotton Candy, Willard Hunnewel
Best Dexter: Heritage Plantation Trophy-Parker's Pink, Jonathan Shaw
Best Azalea: Richard Brooks Trophy-Strawberry Ice,Stephen Snell
Rosebay Trophy: (Judges' Trophy)-R. zoelleri x Princess Alexandra, Willard Hunnewell
Class 1. New rhododendron hybrids-grown by exhibitor-P74. Maurice Hall
Class 2. Low growing ironclads-Yaku "Mist Maiden", Richard Brooks
Class 4. Low growing hybrids-hardy to -15 degrees Yaku Prince, Bob King
Class 5. Medium and tall hybrids, hardy to -15 degrees
5A. Red: Henry's Red Edward Brown
5B. Pink: Mars x yak Willard Hunnewell
5D. Lavender: Avalanche Louis Cook
Class 6.Low growing hybrids, hardy to -5 degrees or tenderer Coral Velvet Richard Brooks
Class 7.Medium and. tall hybrids, hardy to -5 degrees or tenderer
7A.Scarlet (orange reds), Jean Marie de Mont., Stephen Snell
7B.Crimson (blue reds): Wilgen's Ruby Stephen Snell
7E. Pink: Cotton Candy, Willard Hunnewell
7F. Pink with a blotch Mrs. Furnival, Willard Hunnewell
7J. Blue, lavender Blue Peter Louis Cook
7K.Cream, yellow, orange, Goldfort C.F. Eaton
Class 8. Dexter hybrids-
8A. Red: Wissahickon, Chas. Gredler
8B.Pink: Parker's Pink Jonathan Shaw
8C.White Dexter #18 Louis Cook
8D.Lavender, purple Dexter's Purple, Dr. Max Resnick
8E.Cream, yellow, orange Brandywine, Louis Cook
8F.Doubtful Dexters Wheatley Dr. Max Resnick
8. Special Category Consolini Hybrid H. Pilkinton
Class 10.Lepidotes Dora Amateis P. Olafson
Class 11.Unnamed rhodos Mars x yak Willard Hunnewell
Class 12.Species-Fortunei fortunei, Louis Cook
Class 13.Species-Ponticum R. brachycarpum, J. Wright
Class 14. Species-Lepidote R, carolineanum, P. Olafson
Class 16.New Azalea Hybrids grown by exhibitor-Jane Abbot seedling Gus Carlson
Class 17.Azalea Species-R. roseum, Stephen Snell
Class 18. Deciduous A. Mollis-Lemonora Stephen Snell
Class 19 Deciduous A. Ghents Norma Stephen Snell
Class 20.Exbury, Item, Knaphill types-
20A. Red shades: Exbury seedling J. Wright
20B. Pink shades: Strawberry Ice Stephen Snell
2OC. White, cream: Toucan, Gus Carlson
2OD. Yellow, gold:Vel~ow seedling, Stephen Snell
20E. Grange shades: Gibralter, Louis Cook
Class 21.Evergreen azaleas, Gables, Glen Dales, Kaempferi, Vuyks
2la. Red shades: Kaempferi red hose in hose, Stephen Snell
21B Grange shades: Tilly Dr. Max Resnick
21C. Pink shades: Guy Yerkes, P. Olafson
21D.White shades: Wilhelmina V.W., Stephen Snell
21E.Violet, purple, Beethoven, P. Olafson
Class 23. Plants in pots or tubs
23A Specimen rhodo.: Shrimp Girl Bob King
23B.Specimen azalea: Higasa John Cowles
23C Rhodo. bonsai: R. keleticum, Chas. Gredler
23D.Azalea bonsai: Azalea bonsai Chas. Gredler
Class 24.Decorative Arrangement-Arrangement, Robert Doig
Class 26.Malesians R. zoelleri x Princess Alexandra, Willard Hunnewell
Personal Observations Of The Dexter Rhododendrons
BY EVELETH COWLES, with SUSAN COWLES, WELLESLEY, MASS.
Interest in Dexter rhododendrons, as evidenced by the recent listing in the American Rhododendron Society Plant Registry, hints to the importance these plants may have in future breeding programs.
After observing the plants and hybridizing with them for eight years on the Dexter Estate, we have a fair estimate of their potential. We hope that our experience can be of use to others working with Dexter material.
A surprising number of the plantings on the estate did have identification. In some cases this must be taken with a grain of salt, as it has become obvious that plants identified as species were very often hybrids. Those of English origin, such as plants obtained from the Farquhar nursery, are often from open-pollinated seed. As a result, it probably is accurate to describe the Dexter rhododendrons as "Fortune complex" hybrids.
Examples of ones closest to the species fortunei and decorum are 'Dexter's Peppermint' (DE *215) and 'Dexter's Spice' (DE #968). These have tall rangy growth best suited to woodland plantings. On Cape Cod, 'Spice' sometimes lost a few buds and the large blooms tend to develop brown spots. When crossed with 'Dexter's Horizon' (DE #480), it produced seedlings that when grown under light bloomed at thirty months. These were clear pink, fragrant, and weather resistant, but at an early age showed the strongly upright growth of 'Spice'. For anyone intent on fragrance, 'Spice' or 'Peppermint' make a good starting point.
'Dexter's Pink Glory' (DE #219) is an example of other fortunei hybrids. It is completely pollen sterile, but sets seed readily. 'Pink Glory' formed a rather compact bush in an area where it had plenty of space. 'Dexter's Brandy Green' (Dr #491) is another that sets capsules like pickles. This variety combined unusual buff color with pronounced hardiness. It never lost a bud, even after a winter of extended sub zero weather, to -14 degrees F. In common with other cream to buff individuals, the leaves have an olive cast. Some pollen-sterile varieties have very large, intensely fragrant blooms that tend to wilt in a hot spell. 'Pink Glory' and 'Brandy Green' lack fragrance, but make up for it with substance. 'Skyglow' (#9) is a very hardy variety with yellowish leaves. Although it exhibits strong Fortune characteristics, it has moderate growth.
The previous plants are considered by many to be "typical Dexters". Another group in the "For-tune complex" exhibits opposite characteristics -- compact growth rather than lanky habit, and a tendency to nature slowly. These are the decorum x haematodes hybrids that have been sought after by connoisseurs. The blooms usually have a cream to yellow undertone. In varieties such as 'Dexter's Springtime' (DE #314) and 'Dexter's Vanilla' (DE *997) the buds are pink to salmon. The open creamy blooms have either a pink edge as in 'Springtime', or salmon reverse as in 'Vanilla'. 'Dexter's Orange' (DE #296) and 'Dexter's Brick Red' (DE #427) show yellow in the throat, and the rose overlay glows in charming blends of peach to brick. 'Dexter's Orange' has proved an interesting parent. Crossed with R. yakusimanum it produces heavily felted progeny and delicately colored, occasionally attractive blooms. Further hybridizing would probably result in better blooms. Breeding 'Dexter's Orange' to 'Elizabeth' produced compact plants with gorgeous foliage, which unfortunately proved root tender. 'Orange' crossed with dichroanthum hybrids show potential for true orange color. Further experimentation aimed to shorten the time to bloom is needed here.
Although these varieties all have dense low growth, 'Dexter's Brick Red' is conspicuous in being semi-recumbent. This, combined with rich color, makes it a likely candidate in a breeding program. The greatest drawback to growing decorum x haematodes hybrids is that Cape Cod is their practical northern limit. Some have performed well in Ipswich, but they do not bloom every year. In Sandwich, 'Vanilla' frequently lost some pips. This variety had blossoms that were more trumpet-shaped than the others, and probably has different parentage.
An obvious cross for Charles O. Dexter to make was that of the Fortune series with Catawba hybrids. Seedlings were produced and disseminated in great numbers. These developed into hardy robust plants with good foliage and large flower trusses in a range of pinks. 'Dexter's Victoria' (DE #441) and 'Dexter's Appleblossom' (DE #631) are good examples. 'Dexter's Crown Pink' (DE #.600), which Mr. Dexter called "Old Wavy Leaf", has an unusual characteristic. Two or three buds bloom together, forming a massive multiple truss. A lot in Sandwich labeled "Decorum x Mrs. C.S. Sargent" resembles the majority of the plants blooming at the Ben P.P. Moseley estate in Ipswich. A number of these are indifferent in color, but some combine clean tones with attractive ruffling. Some plants of Mrs. C.S. Sargent parentage are picoteed, with a strongly contrasting bright color to the edge of the bloom. As 'Amphion' grew on the estate, it is possible that this two-toned variety was used to some extent in hybridizing.
Doubt has been cast on whether Mr. Dexter used R. smirnowii in his program. A plant of this species is on the estate and although no label exists to confirm it, we believe that crosses were made and carried on to an advanced generation. One small group of plants shows smirnowii derivation by rugose foliage and the elongated rhachis, or central stem, of the whole truss. The best of this group was propagated and named 'Dexter's Horizon' (DE #480). It has open growth, dark foliage (which is unfortunately very susceptible to lace-wing), and the deep pink blooms have a contrasting blotch. Corresponding features in 'Scintillation' lead us to believe that this variety may represent a further generation. It would be very interesting to see if 'Scintillation' would produce felted-leaved progeny using a felted second parent.
When 'Brittania' and 'Pygmalion' appeared on the scene in the early 1930's, they became candidates for further breeding. The question a-rises as to what was produced by Mr. Dexter, and what was produced by his head gardener, Tony Consolini. Tony was a fine plantsman and a spirit of friendly rivalry existed between the two. One of Tony's favorite stories was of how in one case they competed using 'Brittania'. Tony crossed it with a hardy fortune, and Mr. Dexter with a more tender one. Mr. Dexter's cross produced low-growing plants with spectacular blooms, but they were a bit tender. 'Mrs. Coe' is one of these, and the decidedly tender DE #1001 with four inch blossoms remains in the original nursery bed. Next to it are Tony's hybrids, which are much taller, with smaller blossoms in clear pinks. All of these have 'Brittannia's characteristic bowl-shaped blossoms with a waxy texture. Anyone interested in developing hardy reds would be advised to give the Consolini hybrids a look.
Separating Mr. Dexter's work from Tony Consolini's becomes impossible with the 'Pygmalion' hybrids. The parentage in these plants grows more and more complex, at a time when Mr. Dexter was reaching am advanced age. The oldest of the 'Pygmalion' hybrids probably represent a mutual effort, which Tony carried on after Mr. Dexter died in 1943.
'Dexter's Giant Red' (DE #431) bloomed for the first time in 1960, and careful examination traced it back to a seedling started about 1947. It appears that Tony developed some beautiful creams from R. litiense and also griersonianum hybrids of varying quality. The original species plants were acquired by Mr. Dexter. However, he seems to have discounted litiense in breeding, and appears to have used griersonianum briefly.
Hybridizers of the future will not only wish to study the original Dexters, but to consider other material developed as a result of Dexter's love for rhododendrons.
A Personal History Of The Dexter Rhododendrons
BY JACK COWLES, WELLESLEY, MASS.
Memorial Day May 30, 1958 was the start of my experience with the Dexter Estate. Then, for the first time, I saw and explored the masses of rhododendrons which had been set out by Mr. Charles Owen Dexter. By then, some years of neglect had permitted the plantings to be half swallowed by weedy vegetation, green briar, scrub pine, and oak. Contrary to the current rumor, however, the place had not been entirely sacked. Even though most of the smallest plants had been removed from nursery beds, and some of the medium sized specimens were gone, leaving consider-holes, all of the large original plants were still there. These simple conclusions were easily deduced from observing the uneven ground as one tramped the woodland gardens. That same visit led to my meeting with the then current owner, Mr. Berns, Dr. Brown, a former owner, and Mr. Dexter's gardener, Tony Consolini, who was perhaps the most accomplished hybridizer of all. I was most indebted to Tony for much information concerning the plantings and lore of the estate. As a matter of fact, Tony continued his further breeding experiments for three decades after Mr. Dexter died. During the years 1959 to 1967 I was also engaged in perpetuating the recombination of these colorful Asian hybrids. Basic to the plan was the ever present need for greater hardiness, intensification of color, improved choice of plant forms and extension of bloom season.
Mr. Dexter started with catawbiense hybrids then progressed to acquiring Fortune hybrids from Farquhar's Nursery. Then he embarked on a hybridizing program of his own. The building of a small greenhouse in 1930 made it practical to hybridize tender exotic material which needed protection even on Cape Cod. Mr. Dexter used R. haematodes, R. 'Britannia', R. decorum, and R. 'Fabia' in his breeding program. Weather and cultural problems presented some setbacks. Sheer dedication, plus input from other pioneers in rhododendron development such as Ernest Wilson of the Arnold Arboretum, Joseph Gable, Clement Bowers, and Paul Frost yielded many ideas which accelerated programs. Credit should also be given to the collaborative effort; generous swapping of ideas which characterized the big race for improved rhododendrons.
The earliest efforts of Mr. Dexter resulted in his success in growing seedlings in New Bedford just after 1919. In 1921 he purchased the run-down dairy farm which was to be his subsequent home in Sandwich. It was freshly landscaped by Paul Frost, who introduced him to Farquhar's Nursery. By the middle 1920's Mr. Dexter was acquiring Fortune Hybrids by the dozen. He also built a greenhouse for the purpose of expanding his hybridizing efforts, but was not as successful as some would believe. On the average, not more than a few hundred seedlings could have been set out in any one season. Mr. Dexter bad several projects running concurrently on his farm of over a hundred and twenty-five acres. He had two cranberry bogs, an apple orchard, and two peach orchards to tend, besides overseeing his widespread plantings of horticultural material set out over the hillsides on a grand scale. Great glacial hollows were planted with swarms of pink mountain laurel, native azaleas, and select groups of rhododendrons.
Some of these were planted in rows of one distinct kind, then surrounded by groups of hybrid plants. It was not unusual to see R. discolor with R. decorum x R. haematodes hybrids in widely spaced groups.
The first plantings which were brought in from Farquhar's probably were ten years old by the mid-twenties, so that what survived has been around for more than sixty years. Although certain individuals may vary in appearance, those having a common genetic pool behave in a similar way, within the limits of that genetic pool. Thus the Fortune Hybrids all seem to bloom at a specific time, are rather tall course hushes or small trees, often with sparse foliage. Memorial Day at Sandwich seems to be the peak of Fortune Hybrids in most years.
The catawbiense hybrids seem to flower about a week later there. And so it was in 1958 when I first viewed the Memorial Day treasure, this spectacular , beautiful display which Mr. Dexter had set out decades before. As might be expected, Mr. Dexter had added constantly to his collection, even planting out seedlings of some recent imports from some of the plant explorers. Ernest Wilson of the Arnold Arboretum visited the gardens, as did Joe Gable: and they all added to the excitement which caused Dexter to actively carry out his extensive breeding program. No doubt some of his experiments flopped, but the great driving ambition was to search out exotic crosses which would succeed on Cape Cod. It was the Fortunei series which really had the most to contribute with large blossoms. Dexter succeeded in establishing species forms of R. fargesi, R. decorum, R. sutchuenense, R. discolor, and R. fortunei. He set out great thickets of R. carolinianum, plus considerable numbers of hardy plants.
The hybrid cross of R. decorum with R. haematodes resulted in low growing large, waxy flowers with a season of bloom usually preceding the Fortune Hybrids by one week. Mr. Dexter set out three drifts of these on high sloping ground, where they regularly performed very well. These compact plants have flower bud hardiness to zero F., doing well only in the mildest parts of New England. The outstanding beauty of these decorumXhaematodes hybrids has not been fully realized by gardeners until they compare them with the finest European and American novelties. Tony had one specimen which he valued very highly that was a low mound only three feet high at 25 years of age with waxy pink and cream bells.
It is impossible to consider the development of the "Dexter Hybrids" without giving recognition to Tony Consolini. Tony continued the pace set by Mr. Dexter's hybridizing, yet Tony worked with very limited facilities and resources.
The real significance of what Tony and Mr. Dexter were trying to do becomes apparent when one recognizes that the use of tender exotic Asian Material required pits for winter protection. They were reaching out for the unusual qualities found in the exotics. It is fortunate that they were situated in the mildest part of New England, because much of what they were to produce needed all the help they could get from both climate and geography.
R. 'Britannia' was crossed with two different forms of R. fortunei to produce 'Mrs. Wm. R. Coe' in one case and with the other, a group of tallish, hardier pinks with good substance. It was R. fortunei that gave the hardier, taller pink hybrids, while Mr. Dexter's were uniformly low, very large pinks, but only hardy to zero F, Tony then used R. 'Pygmalion' on one of the hardier sorts to evolve an outstanding lot of seedling's, one of which was called 'Dexter's Giant Red'. This variety and all of its siblings show the speckling influence of 'Pygmalion' to some degree. This plant of 'Dexter's Giant Red' did not bloom until 1959, so it can be assumed it was started from a cross made about 1950, unmistakably by Tony Consolini, and is a fitting memorial to Mr. Dexter's great dream.
It becomes apparent that the study of the history of rhododendron breeding shows that progress is measured in decades of effort. Interested individuals within the American Rhododendron Society are in the best position to evaluate and try to secure the gains that have been made. Obviously, a dedicated institutional approach, well founded, and supported by the membership is the best long range way to cope with what should he an ongoing effort.
Robin Hill Azaleas
BY MATTHEW A. NOSAL, WADING RIVER, N.Y.
As the days of May come to an end, the azalea collector is suddenly faced with a dilemma; the garden that was a riot of color throughout most of May is suddenly facing a void, since most of the azaleas are finishing their blooming season. There is still some bloom to look forward to, however, since some of the late Glen Dale and Gable Hybrids are just starting to flower, and in mid-June the Macrantha Hybrids will burst forth with flowers. There are also Satsuki Hybrids that hold promise for June bloom.
Ah, the Satsuki Hybrids! What promise they have for the azalea lover; large flowers, unusual color patterns, beautiful foliage and growth habit, late blooming to extend the season into June. But mostly, they just promise, since they are not reliably hardy north of Philadelphia. They are capable of providing some color in the New York area, but many gardeners find them too much trouble to consider seriously.
If you have ever tried to grow Satsuki Hybrids and found them disappointing, then explore the answer to an azalea lovers' dream come true, the Robin Hill Hybrids.
Bred by Robert Gartrell of Wycoff, N.J., this group of evergreen azaleas offers all those qualities that the Satsukis offer, but they deliver what they promise. They have large flowers, nice mounded growth habits, beautiful foliage, and bloom from late May into early June. However, if you like strong colors, except for a few cultivars, the Robin Hill Hybrids may not be to your liking, since most have very soft, pastel color tones rarely seen in evergreen azaleas. If one compares the color descriptions as listed in the American Rhododendron Society Plant Registry to the appropriate color chart, the flower colors may appear to be flat, or lifeless, but this is how a color chart can be deceptive, Since many of the colors are pastel, or soft, muted tones, the chart cannot show the color as the flower does, but should be used merely as a guide. In many cases, the flower petals are of a texture that transmits sunlight, giving the flower a translucent quality that enhances the basic color. To see a mass planting of Robin Hills in full bloom is a sight to behold. If ambrosia be the food of the Gods, then the Robin Hill Hybrids are certainly ambrosia for the azalea collector.
The goal of Robert Gartrell's breeding project was to produce hardy, late blooming azaleas comparable in flowering characteristics to the Satsuki Hybrids. One of the prime plants in his project was a selected clone of Azalea kaempferi he calls 'Oakland' , which tends to add hardiness to the progeny without changing the desired flowering characteristics of tender varieties in many cases. Other useful cultivars used were Gable's 'Louise Gable', the Glen Dale 'Glacier', and Satsukis 'Shinnyo-no-tsuki' and 'Tama-giku' , to name but a few.
Starting in the late 1930's, Gartrell had made over 1,000 crosses and grown some 25,000 seedlings by the mid 1960's. At present, over 200 have been selected and grown under number, with about 45 of these having been named, and about 25 clones selected for registration. Collections of these fine azaleas exist at the National Arboretum, Callaway Gardens, Planting Fields Arboretum, Tyler Arboretum, and many other arboretums, as well as in Australia, Germany, New Zealand, and Switzerland. Hopefully in the next two years the complete collection will be at the Royal Horticultural Society's garden at Wisley and at Rhododendron Park in Bremen, Germany. (And hopefully, too at the soon to be Mass. Chapter Display Garden-Ed.)
As beautiful and unique as they are, the Robin Hills do not seem to be destined for the commercial success they deserve, mainly because they bloom when general interest in azaleas is on the wane. Perhaps in a few years, as the general public becomes more aware of the vast amount of azalea cultivars available and the lengthened blooming season, some of the Robin Hill Hybrids may become entrenched in the American nursery trade as have some of the Glen Dale and Gable Hybrids. Of course, this goes for not only the Robin Hill Hybrids, but for all the recently introduced azaleas, such as Linwood Hardy and North Tisbury Hybrids, and the beautiful azaleas of Tony Shammarello and Peter Girard. All these superb azaleas should enjoy much greater use in our gardens.
Gerry Benckhuysen of the Homestead Nurseries in Boskoop, Holland, has seen the Robin Hill Hybrids in flower and considers them some of the most beautiful azaleas he has seen. He is hopeful of getting several of the cultivars into the Dutch nursery trade in the near future.
To say that we are saturated with azalea cultivars is an understatement. Just the thought of 454 Glen Dale Hybrids confuses the most ardent azalea enthusiast. When I first heard of the Robin Hill Hybrids, my own reaction was simply, "just another group to add to the confusion". How wrong I was! Now after growing them, I sincerely feel they are perhaps the most beautiful group of azaleas we have available. There isn't another group of azaleas with comparable blooming time that can match the Robin Hill Hybrids for garden display.
Their popularity is established within the American Rhododendron Society, and much of the credit should go to the Azalea Study Group of the New York Chapter. While Bob Gartrell was getting his azaleas established in arboretum collections, and trying to interest nurserymen in them, the New York Azalea Study Group not only became interested in them, but propagated and tested them under varying conditions. Under the guidance of Betty Hager, several of the Study Group members took cuttings of some fifty numbered selections, which they propagated and distributed.
Since most of the Azalea Study Group members reside on Long Island this enabled the plants to be grown under very diverse conditions within a small geographical area. To increase the distribution, plants were offered at the Chapter's semi-annual plant sales, which gave them greater exposure to both ARS members and non-members. As the plants matured in gardens, many comments could be heard at ARS meetings and gatherings about the beautiful flowers, fine foliage characteristics and growth habits of the Robin Hill Hybrids. The gardeners who purchased small plants bearing only a Gartrell number, or members who received rooted cuttings in the initial distribution were enchanted with their newly found treasure, and many sought to grow a complete collection of the Robin Hills.
While many have been named, and those that Bob Gartrell feels are the best of the named cultivars have been registered, it is not unusual for unnamed clones to be sold at plant sales, or searched for by azalea enthusiasts who are constantly searching for beautiful plants for their gardens.
We ARS members should be thankful that in our numbers we have a person such as Bob Gartrell, not only for his genius and foresight, but for his patience; perhaps the one breeding quality that separates the men from the boys. Bob, now in his 80's, is not only selecting outstanding clones of the Robin Hill Hybrids to be named, but growing seedlings from his most recent crosses. Perhaps some of the best of the Robin Hill Hybrids are still in the seedling stage.
DESCRIPTIONS OF THE ROBIN HILL AZALEAS
Following are descriptions of the Robin Hill Hybrids. Included are the parentage, color descriptions using the R.H.S. Colour Chart, and comments concerning growth habit, foliage, and garden value, where appropriate. Last, in parenthesis, are the breeder's plant number, and where applicable, synonyms. These are listed since many of the cultivars were distributed before being named, and some names have been changed to conform with registration rules. Blooming times are for Wycoff, New Jersey area.
BETTY ANN VOSS: (Louise Gable x Tama-giku) x Shinnyo-no-tsuki. Light pink (RHS 62A varying to 62C) 3" hose-in-hose double flowers; blooms late May to early June. Plant habit broader than tall, actually a compact, free branching mound, with beautiful dark green, foliage. A very heavy flowering cultivar, when in full bloom leaves very little to be desired. (U17-8).
CONVERSATION PIECE: (Emil Rosseau x Gable cv. Carol) x Eikan. Light pink (RHS 68C) 3 1/2 single flowers with lighter margins; some flowers with heavy dotting of red (RHS 57B) in blotch area, other flowers with pink sectors, and/or blotch; blooms late May and early June. Mounded growth habit; responds well to, and should be pinched and shaped as a young plant. A very variable cultivar, very aptly named. (T 36-6: Effie Bunce).
DOROTHY HAYDEN: ((Glacier x (Louise Gable x Gable C8G)) x Getsu Toku. White with pale green throat (RHS 149D), 3 1/2" single, flat faced flowers; blooms in early June. A dwarf growth habit; growing about three times as broad as it does tall. (T5-2).
DOROTHY REESE: Glacier x (Louise Gable x Tama-giku). White with pale green throat (RHS 145D), 3 1/2" single flowers with overlapping lobes and wavy margins; blooms late May to early June. A fast growing, free branching, rounded growth habit; very lush, bright green foliage. This cultivar will require more garden space than most Robin Hill Hybrids. (V1-9).
EARLY BENI: ((Louise Gable x (Oakland x Belgian Hybrid)) x Gable cv. Carol. Pale scarlet (RHS 43B), 2 1/2 " hose-in-hose double flowers; blooms in early May. Upright semi-dwarf growth habit. Flowers some-what similar to the Macrantha cv. Beni-Kirishima. (N26-2)
EUNICE UPDIKE: Louise Gable x Shinnyo-no-tsuki. Pale scarlet (RHS 43 C) 2 to 2 1/2" hose-in-hose double flowers; blooms late May and early June. Dwarf, mounded growth; very free branching and very floriferous, with very glossy elliptic foliage. (U22-2; Mrs. Updike).
GLAMORE: (Louise Gable x Tama-giku) x Wako. Pale lavender pink 3" single, occasionally semi-double, flat faced flowers; blooms late May and early June. Very dense, semi-dwarf rounded growth habit. (V21-l).
GLENCORA: Shinnyo-no-tsuki x (Louise Gable x Tamagiku). Light red (RHS 47C) 2 1/2" double flowers; blooms early June. Dwarf, broad growth habit. V5-l).
GRETA: ((Oakland x (Belgian Hybrid x Gable cv. Carol)) x Getsutoku. Dark pink (RHS 58C) 3" single flowers with wavy margins; blooms mid to late May, Low, mounded, free branching growth habit. (T13-8).
GWENDA: (Louise Gable x Tama-giku) x Eikan. Pale pink (RHS 56B) single flowers with wavy margins: blooms in early June. Plant habit semi-dwarf, mound shaped. (T37-4).
LADY LOUISE: Louise Gable x Tama-giku. Pink (RHS 48C) 3" single flowers with slightly darker blotch (RHS 48C); flowers flat faced and occasionally semi-double; blooms in late May. Broad, mounded, compact growth habit, and yet a strong growing plant that will eventually need room to spread out and show the flowers to advantage; beautiful, dark green foliage, glossy. (J44-7)
LADY ROBIN: (Glacier x Tama-giko) x Getsu-Toku. White 3 1/2" single flowers that vary considerably as to amount of dark pink (RHS 66B) stripes and sectors; some flowers will be white with a pale pink wash, or pale pink with an almost white margin, all with or without stripes and sectors; blooms late May and early June. Light green foliage, and broad, sprawling growth habit. (T14-10).
LAURA MORLAND: (Louise Gable x Tamegiku) x (Kaigetsu x Gable cv. Carol). Light pink (RHS 49B) 2 1/2" semi-double flowers with occasional darker stripes (RI'S 4BA); blooms in late May and early June; Compact, rounded growth habit. Very glossy foliage with a maroon tint that is very striking. (U4-l; Mrs. MORLAND).
MRS. EMIL HAGER: (Louise Gable x Tamegiku) x Shinnyo-no-tsaki. Bright pink (RHS 68A) 2 3/4 " semi-double to double flowers; blooms in early June. Hounded, heavy branching dwarf growth habit and very glossy foliage. This is considered by many as a "hot pink"; one of the more vibrant flower colors to be seen in the Robin Hill Hybrids. The growth habit, foliage, and flowering characteristics make this cultivar one of the finer Robin Hills. Suitably named for the person who did so much to make the Robin Hills popular. (U14-5; BETTY HAGER).
NANCY OF ROBINHILL: Vervaeniana x (Louise Gable x Tama-giku). Light pink (RHS 62C) 3 1/2", hose-in-hose double flowers, with occasional light red blotch; blooms in mid to late May. Broad growing, with free branching growth habit. Beautiful in all respects; words cannot describe this cultivar. Named for Bob Gartrell's wife, he considers this his finest azalea. When I recently asked him which cultivar did he think to be the best of all the Robin Hills, he answered with one word; "NANCY". (046-3).
PAPINEAU: Glacier x Swansong. White 3+ ' flowers with pale green throat, and wavy margins; blooms in late May. Very large leaves, 2 1/2" long and almost 1 1/2" wide; very rich green. A large, fast growing, very beautiful cultivar. Perhaps the largest growing of the Robin Hills; certainly the fastest. (R8-5)
REDMOND: (Louise Gable x Tama-giko) x Heiwa. Pale scarlet (RI'S 39B) 3 ' flat faced flowers, with conspicuous dotting of rosy red (RHS 4713) on dorsal lobes; blooms in late May and early June. Very dense, mounded, dwarf growth habit, and large dsrk green round leaves make this a superb garden specimen with year around interest. The pale scarlet flowers, accented by the red spotting create a most unusual effect. (T21-l).
ROBIN HILL GILLIE: Oakland x (( Belgian T'wrid x Gable cv. Carol) x Getsu-Thku)).
Pale orange-red (RHS 42C) 3+" single flowers with wavy margins; blooms in late May. Semi-dwarf, mounded growth habit. (T13-6; GILLIE).
ROBIN HILL FROSTY: Oakland x ((Belgian Hybrid x Gable cv. Carol) x (Louise Gable x Tama-giku)). Bright pink (RHS 62A) 2 3/4 " single flowers with distinct dark pink blotch (RHS 55A), and lighter petal edge (RHS 62')), and very wavy margins; blooms in mid to late May. Plant habit mounded, slightly upright; very free branching and semi-dwarf. A very unique flowering appearance, since the lighter pink margin is just a very thin line along the margin edge, not a band, and almost appears to be white, giving the flower a frosted appearance. The very wavy margins make the flower appear larger than they actually are, and amplifies the frosted appearance. This is a very heavy blooming cultivar. Combined with the good growth habit, the flowering qualities make it one of the best of the Robin Hills. (N31-9; FROSTY),
SPINK: Parentage unknown. Bright pink (RHS 62A) 1 1/2" hose-in-hose flowers; blooms early to mid May. Semi-dwarf, compact, slightly upright growth habit.(K 34-3).
WATCHET: Amagassa x (Louise Gable x Tama-giko). Light pink (RHS 49B) 31/2" single flowers with slightly ruffled margins; blooms in late May. Dense, mounded, semi-dwarf plant habit. (T28-l0)
WHITE MOON: (Glacier x Tama-giku) x Getsu Toku. White 3 1/2" single flowers with a pale green wash (RHS 149D) in the blotch area, and occasional stripes and/or sectors of pale scarlet (RHS 43C); some flowers will be one third to one half scarlet sector, the remainder pure white; blooms in early June. Beautiful bright green glossy leaves give an ideal background for the unusual flowers. Plant habit mounded, branching nicely; but somewhat loose, which tends to show flowers to good advantage. (T17-7).
Rosebay Note: This article on the Robin Hill Azaleas is part 1 of 2 parts, and the second in a series of articles by Matt Nosal describing different groups of evergreen azaleas. (See Rosebay, Spring, 1978, Vol. VII. No. 1 for The Vuykiana Hybrids). Part 1 describes the 22 varieties selected for registration by Mr. Gartrell in 1976. He considered these to be the best. Part 2 will consider the remaining 30 named varieties and also the best of the newer varieties still grown under number.
from the Editor
The Rosebay takes great pleasure in welcoming Alfred J. Fordham as a guest contributor to this
issue. Al for many years was associated with the Arnold Arboretum of Harvard University where he served as propagator of woody plants. While at the Arboretum he developed a great interest and did much work concerning the propagation of Kalmia latifolia. Indeed we believe it a fair statement, that no one person has done more work in this field than he. Although now 'retired', Al acts as a consultant to the Weston Nurseries at which place he is continuing his Kalmia work.
We believe the results of his work are exciting! Any breakthrough resulting in a greater rooting success would remove an important barrier to the further development and greater utilization of these fine plants. Al's work is a giant step in that direction!
Personally I should feel very remiss if I didn't make a special point of congratulating the Mass. Chapter for the Rosebay. It is probably one of the best Chapter publications in the Society. I was particularly interested in the article on the Vuykiana hybrids as I had collected a good many of these at Three Tuns from Henry Holman he-fore he died. I did not move any of these when we moved to Chestnut Hill and I have always been a little sorry. Many of them were good plants.
Alfred S. Martin (Immediate Past Pres. A.R.S.-Ed.)
Do you have a spare copy of the Rosebay, Spring, 1978, that I might have? The azalea articles were excellent and contain original descriptive data that I think might be helpful to the International Rhododendron Registrar, Mr. Brickell, to whom I will send the copy. Thank you for your help.
Ed. Parker (Registrar, A.R.S.-Ed. )
Charles Owen Dexter died 35 years ago. Yet the significance of his legacy to the rhododendron world is only now being properly assessed. Unfortunately it seems that the passing of such a lengthy time interval is almost a prerequisite--by which time most, if not all, of the principals have passed On There are however two individuals, very much alive, whose experience makes them a definite part of the Dexter picture. Sometime in the spring of 1959 Jack and Evvie Cowles arrived at the Dexter Estate, Jack to assume his duties as Horticulturist under Mr. Stanley Berns, the then owner. For a period of over eight years Jack (and Evvie) literally ate, slept and lived Dexters. This included an extensive study of the plantings, evaluation, selection and naming of superior varieties, as well as limited propagation and further hybridization.
During this period Tony Consolini, for many years head gardener for Dexter, was still alive and lived close by. A good friendship developed resulting in access to invaluable information personally obtained from Tony, based on his own many years of observation and experience.
This then is the background for the articles by both Jack and Evvie in this issue. 'Personal History Of The Dexter Rhododendrons' first appeared in the Rosebay, Fall, 1975 (Vol. IV, No. 2). Since that issue is out of print and as undoubtedly many of the Rosebay's now much expanded readership have not had the opportunity to read it, we reprint it now.
Wishfully, Jack and Evvie in the near future could see fit to expound upon their unique experience. The rhododendron public would eagerly receive such an endeavor.
Hardening Off Rhododendrons and Azaleas
BY LLOYD PARTAIN, POTTSTOWN, PA.
Survival and healthy growth of rhododendrons and azaleas during that most critical first year alter they are rooted from cuttings or propagated from seed may depend greatly on proper hardening off. The plant tissues-roots, stems and leaves-whose growth have been stimulated by artificial light and heat, need to be conditioned by a hardening process to help them adjust their physiological and nutritional functioning to better withstand a more rigorous environment-in the cold frame, liner bed, or wherever else they may be transferred.
Too much nitrogen can prevent formation of flower buds.
AT LEAST THREE CULTURAL PRACTICES DURING THIS PERIOD HAVE PROVEN HELPFUL:
1. The application of at least three plant food elements-potassium, phosphate, and magnesium (no nitrogen), well in advance of on-coming winter. I find August 1 to 15 to be an excellent time in my garden. A formula of 0-l0-l0 or 0-l2-l2 takes care of the phosphorous and potassium requirements. Application of this formula in granular form at the rate of 2+ lbs to which is added 3/4 to 1 lb of magnesium sulphate (Epsom salts) per 100 square feet of growing area rounds out a good mixture. All these elements are necessary to hasten hardening and maturing of plant tissue.
2. Inoculation of soil with a helpful fungus. If the growing medium in which one or two year old cuttings or seedlings are to be transplanted does not naturally contain soil derived from woodland, it may be lacking in a strain of fungi very important to rhododendron assimilation of necessary plant food elements. The fungi are called mycorrhiza. Certain strains of the genus rhododendron seem to thrive in symbiotic relationship. A sure way to assure the presence of this beneficial fungus is to mix some woodsy soil, preferably taken from an area where ericaceous plants grow, into the root zone area of new plantings.
3. Mulch management. A common and excellent cultural practice is the use of a fairly heavy organic mulch in spring or summer to conserve moisture, maintain desirable soil temperature, and control woods. A heavy mulch left on young plants during late autumn may result in severe injury and possibly death. The insulation effect of a heavy summer mulch does not permit the soil beneath to cool down sufficiently during cool nights of autumn. The plant tissue at soil level and above to the depth of mulch remains soft and tender. A sudden plunge of temperature to well below freezing results in bark-splitting and other damage. Research studies with azaleas have shown that a lighter mulch maintained in fall and early winter, until some frost is evident in the soil, materially reduces bark-splitting. After this soil temperature is attained I find the application of a heavier winter mulch advantageous. It may be important therefore, to pull away from young plants much of a heavy summer mulch as cold nights begin to arrive and replace it after hard frost. In the area where I live (Northern Chester County, Pa.) I find the time to do this to be usually late December. Weather and soil conditions rather than the calendar should govern the time for this practice.
Most rhododendron and azalea gardeners grow young plants in soil in which substantial amounts of fibrous organic matter have been incorporated-and rightly so. Most such materials are naturally low in plant food elements such as nitrogen, phosphorus, and potash. Most soils, especially in the eastern part of the United States, are deficient in these and other necessary plant food elements such as magnesium, iron, calcium, and manganese. This being the case it is helpful, even necessary with many soils, to add these elements in proper amounts in order that young plants become well established. (Of course a complete soil test serves as the best guide as to which elements and in what amounts are needed.)
The addition of certain of these plant food elements is especially important in the hardening-off process.
Of course Nitrogen is a key element in the functioning of chlorophyll and therefore necessary to healthy plant growth. But in growing azaleas and rhododendrons it should he used with caution. This is doubly important to their survival in the early stages of their growth. Too much has the injurious effect of causing rank growth. The rank plants usually lack stiffness of stem and leaves. They are usually not resistant to cold or hot weather. The plant tissues are not rigid enough to withstand wide variations of temperature and moisture conditions. Too much nitrogen can prevent formation of flower buds. My recommendation: use nitrogen sparingly- however slightly heavier amounts should be applied where heavy fibrous mulch is used. Only sulphate of ammonia or materials containing organic nitrogen such as cottonseed meal should be used. Never apply to young plants any nitrogen-bearing fertilizer after June 15. I find an early application of no more than one pound of sulphate of ammonia per 100 square feet in my liner beds to be about the right amount.
Phosphorus is required for optimum formation of all plant cells and, therefore, important to sturdiness of growth-hardening tissues. It is very important to bud set and quality of bloom. Most soils in eastern United States are deficient in a form available to plants and therefore,
should be added to assure sturdy growth and quality performance. Phosphorus, as well as nitrogen, is required by bacteria in the decay of mulch and other organic material usually used in growing on rhododendrons and azaleas. Its presence in the soil in adequate amounts is very necessary to flower bud formation. A soil test is advisable as a guide to amounts to apply.
It has long been known that the formation and movement in plants of starches and sugars, which plants must store in their tissues, as the food for future use are directly related to the availability of potash in the soil, moreover, potash has an immediate beneficial effect on the proper development of leaves and branches. It helps to make them strong and stiff- important in resistance to extremes in temperatures and to many diseases. Potash also promotes flowering qualities. Insufficient potash in soils can also effect the availability to the plant of that important minor element--iron. Indeed, the early effects of insufficient potash--chlorosis condition- are very similar to iron deficiency. Rhododendrons and azaleas do not require as much available potash as do many field crops and other cultivated plants; but small amounts are very necessary to their good health and performance. This is especially true in their younger stages of development.
In "Rhododendrons of the World", by David G. Leach, published by Charles Scribners Sons in 1961, the following statement is found on page 286:
Magnesium is a chemical component of chlorophyl4 the energy factory for all green plants.
"I suspect that the beneficial effect of magnesium in the nutrition of rhododendrons has been grossly undervalued." My experience surely indicated the truth of that statement. I should mention that most of my efforts at growing azaleas and rhododendrons have been in heavy to very heavy soils. By my own experimenting I have found that the addition of small amounts of magnesium sulphate (Epsom salts) alleviates a chlorotic and weakened condition of affected plants. Magnesium is a chemical component of chlorophyll, the energy supply factory for all green plants. It is often not available in sufficient quantities in clayey soils and must be added--in small quantities of course. About one pound per 100 square feet of liner beds seems adequate. It makes heavy soils seem lighter and fluffier on the surface where the roots feed.
One last note on rhododendron and azalea nutrition is important to this discussion about clayey soils. The addition of calcium sulphate (gypsum) has both a chemical as well as physical effect on the improvement of such soils. Here again, a soil test should guide the rate of application. I have found on heavy clay soils that two pounds per 100 square feet of growing area not to be excessive. It seems to stimulate root formation of young plants. Calcium, if needed, should only be used in the SULPHATE form. Avoid ground limestone or calcium carbonate in rhododendron and azalea growing. In fact it will be noted that all the plant food elements discussed herein are of the "sulphate" form: making them safe fertilizers for acid-loving plants.
Insufficient potash in the soil can affect the availability to the plant of that important element-iron.
Note: Since the above was written Dr. August E. Kehr, (then) President of the American Rhododendron Society, in speaking before the annual banquet of the Philadelphia Chapter, referred to new research begun in the Pacific Northwest on mycorrhizal-rhododendron physiological interdependence. This, indeed, is good news. The importance of several strains or varieties of this beneficial fungus to forest tree growth has been well established in recent years. More needs to be known about the fungi culture and use in the growing of the genus, Rhododendron.
Rhododendrons of the World-David G. Leach- Charles Scribners & Sons, New York
Azaleas; Kinds and Cultures-H. Harold Hume- The MacMillan Co., New York
American Rhododendron Society Bulletin (Various issues since 1969)
A Visit To Exbury
DOROTHY SWIFT SAUNDERSTOWN, RI.
It was a pleasure to visit Exbury Gardens in England for the second tine on May 2, 1977. From my previous visit there (May 9, 1974) in the late mid-season of a typical fine spring, I already knew what a display Exbury could show at its best. The spring of 1977 followed the drought of summer 1976 and the deluge of fall 1976 and a series of late frosts in the spring, so flowering was just beginning. Exbury, like Wisley, showed less damage than many other gardens. This probably results in part from efforts put into watering during the drought, but I think it is also a reflection of working constantly to keep the garden rejuvenated and attractive. Gardens with primarily old plants had much more damage.
There is some hybridizing going on at Exbury still, but not on the scale that Lionel de Rothschild maintained, because the effort and space are needed for the propagation of plants by the nursery there. Mr. Peter N. Barber, one of the managers of the estate, sees as useful goals for hybridizing the creation of more compact plants having flowers of the size and quality of the Exbury Hybrids, (And of course, for us, plants with sufficient hardiness to grow well over a wider region).
Mr. and Mrs. Barber have had the opportunity to observe the Rothschild rhododendrons through the course of the season and over many years. Mrs. Barber's favorites are the Naomi clones and R. calophytum. Mr. Barber's favorite's are 'Elizabeth de Rothschild' ('Lionel's Triumph' x 'Naomi Exbury'), deep cream flowers with chestnut spots in the throat and 'Repose' (R. lacteum x R. discolor) creamy white with speckles in the throat, giving an overall impression of pale lemon. These plants are not widely distributed in the trade yet. He cites the clones of the Fred Wyniatt grex (R. fortunei x 'Jalisco')
-'Jerex', 'Joyful', 'Simita', and 'Trianon' as fine hybrids of yellow, cream, maize or rose which are not yet well known. Other plants which he feels to be among the best of the Exbury hybrids, with emphasis on ones not widely grown are: 'Edmund de Rothschild' (Kilimanjero x Fusilier, late deep red) : 'Jalisco' (Lady Bessborough x Dido) clones Exbury, 'Eclipse', 'Elect', 'Emblem', 'Goshawk', 'Janet', 'Jubilant' and 'Lindberg' are all yellow: 'Grenadine' (Pauline x R. griersonianum, cerise): 'Galactic' (Avalanche x R. lacteum, deep cream with crimson eye) : 'Abalone' (R. camplocarpum x R. callimorphum x R. camplocarpum, apricot-lemon-straw blend): 'Exbury Cornish Cross' (R. thomsonii x R. griffithianum, crimson): 'Cara Mia' (Aurora x Crest, rose and cream) : 'Nicholas' (one of few which parentage is unknown, perhaps R. ponticum genes, bright glowing purple): 'Jocelyne' (R. lacteum x R. calophytum, lustrous mother-of-pearl tone with crimson mark). Mr. Barber's favorites among the species are R. fulvum, R. pseudochrysanthum, R. souliei, (exbury P.A. form), R. wardii. A few years ago he would have included R. yakusimanum (Exbury form), but that plant is receiving sufficient attention that other species need a boost.
Among plants worthy of trial in eastern North American gardens he considers one with mid-season bloom to have a better chance of survival. For example, the Naomi clones seem to show a great deal of hardiness from the R. fortunei parent or the vigor of hybridity. 'Naomi' is Aurora x R. fortunei. The Fred Wyniatt group, previously mentioned, are R. fortunei x Jalisco and are also worthy of trial. He suggests that 'Jalisco', 'Lionel's Triumph' (R. lacteum x Naomi), and 'Elinore' (R. desquamatum x R. augustinii) are deserving of more widespread trial. 'Naomi' and 'Elinore' are rated H3 in the United States, 'Jalisco' is rated H4, and I do not know the ratings for the others. However, 'Naomi' seems to show as much hardiness for me as H2 plants, and plants rated H3 or H4 on the U.S. West Coast simply have to be tested.
It will be of interest to grow Naomi clones with some of the pink Dexter hybrids. Both groups were hybridized around the same time and have some R. fortunei genes. It is difficult to explain the fine texture and opalescent shading that I have seen in flowers of some Naomi plants, but it is a different effect than the widely distributed pink Dexter hybrids have. I hope some of us can see the two groups in the same garden.
Mr. Barber suggests the species R. campanulatum, R. souliei, and R. wardii, if you try to locate good forms. Various R. yakusimanum crosses have good compact growth and attractive flowers and usually show H2-H3 hardiness even with the other parent very tender. Also suggested is Baden-Baden, a hybrid from Germany which is a very hardy plant but one which has flowers as fine as the more tender hybrids.
When one visits a garden, on any particular day, there is often one plant which stands out as being at its own peak of bloom such that it overshadows most other plants. This time it was 'Carita Inchmery' (Naomi x R. campylocarpum) which had a biscuit colored flower with rose tones in the center that makes it glow. Second place went to 'Crest' (R. wardii x Lady Bessborough) with its orange and yellow flowers, all of the plants well budded despite the bad year preceding and looking like really fine large plants for the woodland garden. (In New England, many of us are growing 'Crest', rated H3, whereas 'Carita' clones are rated H4 and present more difficulty). I lost one after several years of its holding its own. Gay Arsen (2) in the December 1974 NY Chapter Newsletter tells of how 'Carita' finally found happiness on the south shore of Long Island after 10 years in a north shore garden where flower buds were always killed by frost)
The Exbury Estate in Hampshire covers 2600 acres. Edmund de Rothschild, son of Lionel de Rothschild, lives there now, as do his two sons and their families. Exbury Gardens Ltd. and Exbury Trees Ltd., are nursery operations on part of the land in order now that some of the expenses of the estate can be met. In this age, the greenhouses can not longer hold orchids and fruit trees, but are filled with benches of cuttings, grafts, etc.. Activities center around the propagation and sale of trees (Mr. Barber, manager) and of ericaceous plants (Mr. Harris, manager). The latter include rhododendrons, deciduous and evergreen azaleas, camellias, Pieris, etc. The propagation of rhododendron involves almost 100,000 cuttings set per year. This results in about 20,000 to 30,000 medium to large growing rhododendrons and 30,000 to 40,000 of dwarf varieties. Those varieties which normally root with less than 50% success from cuttings are propagated by other methods. About 5000 are grown from grafts on other stock such as R. ponticum or R. calophytum. The most interesting method to me was propagation by layering. There are a number of large beds into which mature plants are brought and the branches are neatly positioned to produce rooted layers. The success of this method depends on having someone who knows how to do it rapidly and properly, and Exbury is fortunate to have an experienced gardener for this. About 5000 to 10,000 plants are produced by this method each year. Some of these are the most attractive of Exbury hybrids, varieties which have not been propagated and distributed extensively because they do not root rapidly under standard propagation by cuttings.
Exbury Gardens are open to the public each spring, every afternoon from 2 to 6:30 from the first Sunday in April to the second Sunday in June. Admission is 50p (about 85 cents). The location is several miles from the village of Beaulieu where there is a hotel (The Montague Arms), 9 miles from Brockenhurst and 15 miles from Southhampton, both of which have trains and hotels. If you can write or call in advance of your visit, the people at Exbury are happy to help make travel convenient and to give extra garden time and their own attention to rhododendron enthusiasts.
(1)Barber, Peter N. and C.E. Lucas Phillips: The Rothschild Rhododendrons, Cassell & Co. Ltd. London, 1967 (History of the estate, parentage and description of all the Exbury hybrids, color photographs of many).
(2)Arsen, Gay: A Story With A Happy Ending, Newsletter, N.Y. Chapter, A.R.S. Vol. VII, No. I, 1974.