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Journal American Rhododendron Society

Current Editor:
Dr. Glen Jamieson ars.editor@gmail.com


Volume 6, Number 2
April 1952

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"Rhododendronitis"
by Gwillt King

        There are many different kinds of horticultural disease to which the amateur may be susceptible. They vary in their symptoms, duration and virulence. They may attack at any season of the year, although the winter and spring months are undoubtedly the most dangerous. The mildest form, certainly the most common, is ordinary "gardenitis" which comes on in mid-winter, coincident with the arrival, by mail, of the Burpee catalogue.
        We can imagine the amateur sitting in a comfortable chair before a crackling fire, listening to the rain and gusts of wind outside. His eye chances to fall on the bright cover of the seed catalogue which his wife has ordered. He picks it up and casually thumbs through it. From the pictures he turns to the written descriptions and notes the absurdly small cost of the precious packets of seeds. Only 58 days from the seed to that perfect Big Boy tomato which weighs a full pound! The only evidence to indicate that the amateur is being needled is a slight quickening of his pulse and a gentle salivation. In his mind's eye he is watching himself strolling through his own garden, plucking the magnificent sprays of gladiolas or gathering bushel baskets full of succulent cucumbers, peas and tomatoes, each specimen the exact replica of that shown in the color plates. As a matter of fact, this form of gardenitis is the most pleasant and least dangerous of the horticultural diseases. Light infections may abort before the ground can be turned in the spring and the more persistent infections are usually cured by a few seasons of drought, pests and sore muscles. There are, of course, a few more virulent forms that can be brought on by catalogue contamination, such as the fruit tree type, of which the dwarf variation seems to be the most serious.
        Once the amateur has recovered from an attack of gardenitis, he considers himself immune from all other kinds of horticultural disease. This assumption has proven to be unfounded. It is true that his attack has made him relatively immune to that one disease, and in some instances a certain degree of crossed immunity for other outdoor forms is conferred. But this is not to be relied upon, and he must be constantly on the alert to avoid the more deadly types, such as the dread "rhododendronitis." I would list this disease as the most dangerous of all the horticultural diseases, with the possible exception of "acute orchiditis." Statistical studies by the department of agriculture suggests that more Oregonians are struck down annually by rhododendronitis, and either maimed or temporarily unbalanced by this disease, than are injured in falls when they step on the soap in their own bath tubs. It is for the purpose of bringing such facts to the attention of the amateur and to briefly outline of the salient features of rhododendronitis that this article is being written.
        Rhododendronitis begins insidiously, passing through a series of stages which progress to a crisis that may either kill or cure. The first stage is that of "inoculation." This never occurs during the winter months since there are few catalogues with color plates and prices are sufficiently high to protect the uninitiated from contamination. Most inoculations occur during the month of May, somewhat in the following fashion. Let us say that it is a Sunday morning and the amateur has just settled down to enjoy the funny papers. His wife suggests a drive through the arboretum or a visit to a friend's estate. After a brief skirmish, during which the amateur already knows that he is going, they phone the friend and drive off in the family car. On reaching the garden spot, the amateur wanders off by himself. In his present foot-dragging mood, he finds it difficult to respond appropriately to his host's gentle boasting and the spritely comments of his wife. Suddenly, he comes upon a planting of magnificent rhododendron hybrids in full bloom. The dignity of their massive trusses and their gorgeous colors against the dark background of green foliage, stirs him as no catalogue has ever stirred him. He calls to his wife to come look! He has the overpowering conviction that he must have "one of those red ones" for his own garden. He is almost ready to commit himself aloud on this decision, but the brief wait before his wife joins him, gives time for his natural caution to assert itself. The memory of his recent fruit tree attack is too fresh in his mind to permit him to commit himself until he knows better what he might be letting himself in for.
        By cautious questioning of his host he learns that the raising of rhododendrons in western Oregon is mere child's play. The rhododendron, he is told, is singularly free from plant diseases and pests. The acid soil, the friendly environment of firs and dogwoods and our salubrious climate are exactly suited to this genus. Not only can we raise the more hardy types seen in the eastern States, but our mild winters, perhaps I should say "usually," or better, "occasionally" mild winters, permit us to grow many of the exotic species which have made English gardens so famous. Finally, the enormous range of color, foliage and size among the many species make it possible for the amateur to use this plant to adorn a great estate or the tiniest of rock gardens. Once the amateur has accepted these postulates, the stage of inoculation is complete.
        The second stage is that of "incubation." This phase is usually symptom-less until the first visit to a commercial nursery. This visit should be made in the spring when the rhododendrons are in full flower so that the amateur may see exactly what he is purchasing. This first visit may bring on a transient giddiness. It passes as soon as prices are mentioned and is replaced by the first twinges of real pain. The victim is overcome both by the prices and the varieties with which he is confronted. The "red one" which he saw in his friend's garden is no longer quite clear in his mind. He wishes that he had paid more attention when its name was mentioned. There are a number of red ones here in the nursery. All of them seem equally lovely, yet it appears that their prices vary in a manner that is completely incomprehensible to the amateur. It is doubtful that he will ever fully understand the basis for a nurseryman's prices. His first assumption, that they are based on size, conformation and the number of trusses on the plant, proves untenable when he discovers, at the rear of the nursery, a group of large and very lovely rhododendrons with trusses of delicate lilac shades, which can be purchased for a fraction of the cost of those in the front display beds. These "off-color" rhododendrons are evidently not of the aristocracy. There is also a surprising range in prices among their more respectable relatives. The amateur hears vague mention of "A. M.," "F. C. C.," "Stars," "English and American ratings" and "clones," all of which are a meaningless jargon to him and yet which appear to have a direct bearing on prices. It now appears that the "red one" on which his choice has finally settled, received an A.M. in 1939, an F.C.C. in 1942 and is a clone from a hybrid. Assured on these vital statistics the amateur parts with his hard-earned dollars with few outward manifestations of his inner suffering. But as he drives thoughtfully homeward, he needs must glance often at his beautiful prize to ward off the depression that creeps over him when he considers the contrast in the probable cost ' of up-keep of his present illness and that of his last attack of gardenitis.
        The disease frequently passes through both a hybrid and a species stage as its virulence increases. The species phase is always the more toxic. Yet the full potentialities of rhododendronitis do not appear until the stage of "propagation" is reached. The onset may be insidious, starting perhaps when a branch of his favorite specimen is broken off by that infernal dog of the neighbor's. Hoping to save at least a bit of it, the amateur prepares cuttings from it, repeating, as well as the can remember, the methods he has seen the nurseryman use in putting cuttings into a flat of moist peat moss. To his amazement, three of the 58 cuttings take root! Now his fever begins to rise and there appear behind his house in succession, a cold frame, a hot frame, two lath houses and a greenhouse. By this time the amateur is a sick man. Enough of his cuttings root to keep him constantly transplanting. Not only is there a persistent moving of plants from rooting bench to flats, from flats to lath-house, from lath-house to beds and from beds to permanent plantings, but it always seems that changes are necessary :n the permanent plantings due to classes of color, too much sun or too little sun and the like. There is no need to dwell on the details of the propagation stage since those who have been through it already know all about them and those who have never suffered from it would be totally unable to appreciate them.
        But the real crisis in the progress of rhododendronitis comes when the amateur starts to make his own crosses and conceives the brilliant idea that he can breed a "perfect" rhododendron combining the best features of all rhododendrons. He can already imagine the thrill there will be in naming it himself, and modestly accepting the T. G. C. it will receive from the American Rhododendron Society. Unfortunately, this project calls for a bit of study. What are the features he must seek and what species are most likely to possess them in their germ plasm? Perhaps he had best limit himself at first to seeking just ten of the desirable features he has been thinking about and not try to get the perfect specimen all at once. As his reading widens he discovers that many of the crosses he has been considering have already been made by English propagators many years ago. Each of the resultant hybrids already has an official name. Even if he bred a particularly desirable plant by making this particular cross it would have to take that name. Since this would apply only to the F-1 generation and not to the F-2, it is apparent that he will have to carry his experiment at least that far to attain his objectives. Furthermore, it is entirely possible that all ten of the features he is seeking might not appear even in the F-2 generation. Therefore, he had best plan on going at least as far as the F-3 generation.
        At the time of its inception, this plan seems highly desirable and perfectly feasible to the amateur. He decides that he might as well start by crossing two of his favorites, R. thomsonii and the hybrid R. 'Unique'. He is unable to run down the parentage of 'Unique' but thinks that it probably contains the blood of R. campylocarpum. At any event, the crossing of these two should create some lovely combinations of the creamy white of the R. 'Unique' and the translucent, blood-red color of R. thomsonii. So, he used the R. thomsonii as the male parent and the R. 'Unique' as the maternal parent. This first cross does not turn out as well as he had expected. Evidently he tore open the flowers of 'Unique' too soon and applied the pollen before the pistils were ready to receive it. At least, only one of the flowers on this truss produces a seed pod. The precious pod is carefully dried and the seed strewn with the utmost delicacy. Of the seeds, approximately half fail to germinate. A slight touch of damp-off sharply reduces the number of surviving seedlings. A few more of them wilt when he lets the peat moss become a bit too dry at the margins of the container. But the remaining seventy six seedlings show great promise. Their cotyledons and stems show exciting variations in size and color! By the time their permanent leaves appear it is practically certain that the experiment will be a huge success. Pricking-off reduces the number of survivors to forty nine. A worm clips off another nineteen. During the first year a number of mysterious afflictions reduce the assembly to seven specimens. All of them survive the second season and are now sturdy little plants almost as tall as his little finger.
        As the amateur watches this slow progress with a paternal eye, the first vague doubts arise about his original project and its feasibility. Let's see now, how are we progressing? Experience has indicated that R. 'Unique' is quite a precocious plant and its cuttings have grown to flowering stage in three or four years in certain instances. R. thomsonii, on the other hand, can not be expected to bloom until it is ten or twelve years old. Say we split the difference and assume that it will be seven years between seed and flower in these seven representatives of the F-1 cross. Allow another year in which to make the F-2 cross and seven more for the seedlings to flower. Another year will see the production of F-3 seeds and it should take no more than seven more for the experiment to be completed. In other words, we should know whether we really have something or nothing well within a quarter of a century.
        But it is not the number of years involved in this experiment, or the worry over whether or not he will live that long, which drives the amateur stark mad. It is his vision of the geometrical progression in the number of seedlings, the acres of filled flats, the years of spraying and transplanting, and the endless succession of damp off, prick-off, and label-off which confronts him. Here is the true crisis in a full-blown case of rhododendronitis. The prognosis now will depend entirely on the amateur's fundamental make-up. If he sucked his thumb or wet the bed as a child, or even if he is simply stubborn by nature, it is high time to call in the psychiatrists. But if he has a lick of sense, he will come down to earth and be deeply thankful that only seven seedlings of his F-1 cross have survived. With this decision he begins to relax, the film passes from before his eyes, sanity is restored and he begins to get well. That he is not yet fully recovered is indicated by the fact that he is still interested in seeing how his seven seedlings turn out, but his fever is gone and the prognosis for the future is good.
        (SUB-NOTE-In view of the prevalence of rhododendronitis and its serious nature, I have given considerable thought toward starting a "Rhododendronitis Foundation." Its primary purpose would be to collect a dime from those who do not have the disease to aid those who do. The mere fact that any citizen might suddenly come down with this dread condition should open his heart and loosen his purse strings. By keeping this Foundation completely separate from the "Community Chest" drive (as so many other worthy charities have managed to do) the "take" would not have to be split with others and might develop into quite a good thing. Anyone interested in the idea may write me in care of the editor. Be sure to enclose your dime.)


Volume 6, Number 2
April 1952

DLA Ejournal Home | QBARS Home | Table of Contents for this issue | Search JARS and other ejournals