Some Rhododendron Experiences
Geoffrey Wakefield, Director, Rip Van Winkle Gardens, Jefferson Island, La.
Paper presented at the Southern Chapter Annual Meeting, Fayetteville, Arkansas, May 30, 1967.
To the members of the Southern Chapter of the American Rhododendron Society - Mr. President, Ladies and Gentlemen: First I must thank you most sincerely for the great honor you do me in asking me here to speak to such an august and expert company. Secondly I must thank you all for the welcome you have given me to this conference and the welcome all Americans have given me and my family to your lovely country.
To address such a company of experts upon their own pet subject is, to say the least, frightening. Therefore, I propose to talk to you about rhododendrons, not here in America so much as in other countries where I have experienced them.
Mr. Coyle, who follows me in addressing you, has had much more experience with them in this country and will be telling you some of the troubles you will experience and how to remedy them. I would therefore ask you to bear in mind some of the things I shall be telling you so that you may tie the two lectures in together.
My first experience with rhododendrons came as an apprentice gardener under my father and I regret to record that I paid both my father and rhododendrons far less attention than I should have. After this, I proceeded, via the British Army, to India where I served with the Royal Corps of Signals. This was a most fortunate choice of service since the trade corps are frequently detached into small units, in wild and inaccessible areas seldom seen by the main body. This to a gardener can be enormously interesting, and in 1940 I had the great good fortune of being posted to Jalapahar, the military station some 4 or 5 miles from, and 2,000 ft. above, the better known Darjeeling in the Himalayas.
Major George Sherriff, V. M. H., the world famous collector, had just come down from Lhasa, capital of Tibet, and it was he who really inspired me to team up with another soldier whose main preoccupation was climbing mountains. All our spare time was taken up in exploring and collecting.
The area around Darjeeling consists of steep hills separated by deep valleys. The floors of these valleys are narrow, sometimes a few hundred feet; and may reach down to below 2,000 feet. The hills above go up to over 8,000 feet. Some three days from Darjeeling by car and mule is San Dak Phu, a Buddhist monastery with an altitude of 12,500 feet. This we visited, taking the hard way, laying a sight on the hill from Tiger Hill, then marching in a straight line. Since we were travelling without any sort of stores or special equipment, or with guides, it may be imagined just how interesting the journey was. Buying or begging food and shelter, or sleeping on the hillsides, the journey took more than twice as long as that taken by the tourists but our reward was in the scenery and plants we saw and in the friends we made.
Later explorations took us right up to the Tibetan border where the elevation is around 14,000 feet. This is well up into the winter snow line. The winds are searingly cold, and even in summer, sheltered from the burning sun, one needs wind-proof clothing. Plants here are extremely hardy. They have to endure long periods of drought. The winds draw moisture from them and the sun burns them. In winter they may either spend months beneath the snow or be subject to biting winds. One sees mostly types centered around R. lepidotum. This species is variable both in habit and color. On the high passes it grows much as the heathers of Europe--about knee high, varying from pale yellow through indifferent pinks and mauves to good, purple blues. In England the same species may grow to 4 or 5 feet high. I did not find the colors so good nor the plants so exciting as those of the Lapponicum series we saw growing under similar conditions in the Chunking area.
Many of these plants, I am quite sure, could well he adapted to grow in the Rocky Mountain area, probably in the hills of Texas and further East. In nature they favor shallow pockets of deep brown, peaty soil, the accumulations of years of vegetable matter mixed with rock weathering-. They grow also in the close turf of the high mountains and even on the actual rocks which have a shallow covering of turf or peaty soil. The roots are able to work out into rock crevices, anchoring the plants firmly against winds and providing food and moisture. The leaves have become adapted into narrow, rolled, almost fir needles, presenting a small surface to the sun and wind.
Rainfall is fairly high during the spring growing period, the Himalayan monsoon breaks on or about the first of April, tapering off by about July. There is often a second spell of rain in September, otherwise plants have to rely on winter rain or snow.
Dropping down to the 10,000 to 12,000 foot range, one begins to find R. thomsonii, campylocarpum, campanulatum and the hardier forms of arboreum to name but a few. R. barbatum seems to be everywhere and there is no lovelier sight than this and R. arboreum, in full bloom, festooned along the branches, and on the vines growing upon them, with multicolored orchids.
At 8,000 feet one sees the choicer forms of R. arboreum, the deep blood reds with bigger, handsomer foliage. Major Tom Spring-Smythe, liaison officer for the U.N.O. with the Nepali government, is in the area at this time and will he marking a number of plants for seed collections later. He showed me a collection of arboreums and others he had made around Kathmando and which were growing in the gardens of Wakehurst Place, now the new country home of the Royal Botanic Gardens, Kew. The variations in leaf and flowers are quite interesting and we believe that one only gets the best colors, the deep glowing reds, from the low altitude collections. The pale and indifferent pinks and whites are from high altitude forms. Certainly observations of hardiness of plants growing in England tend to substantiate this. The high altitude leaves tend toward a dull, (lark green; the indumentum toward a metallic sheen. The low altitude forms could almost pass (in color) for the leaves of barbatum, some being almost devoid of indumentum.
In the valleys the temperature and humidity in summer are very high. Difficult as it is to breathe on the high passes, through lack of oxygen, one becomes accustomed to it in a couple of weeks. Breathing the heavy oppressive atmosphere of the valleys is much worse. On the hills one feels enormous exhilaration and we thought nothing of taking a 20 mile stroll in the driving misty rains of the Himalayan monsoon. In the valleys we moved only through will power and through the urge to get out into the fresh air again.
In these valleys we found rhododendrons of the Edgworthii and Maddenii series. Growing mainly as epiphytes on the moss of other trees or in dead tree stumps, some seedlings could even be found growing in the moss festooning the vines which hung from the forest trees. This is jungle proper--very beautiful, awe-inspiring, almost frightening. Of the species down here, I found lindleyi and nuttallii the most, spectacular. Further east is found the even more magnificent sino-nuttallii and taggianum.
It is these species which I believe give us great hope for rhododendrons along the warmer, more humid areas of the Gulf coast. Having experienced the climate and humidity of both places and having seen and lived in both areas, I see little reason for not trying them here. It is to me a thing of great pity that there is not a well set up and equipped Botanic Garden where we could experiment with this type of plant. In the Himalayas they grow, as I said, epiphytically in moss and dead tree stumps. In the Gulf coast area are magnificent Live Oaks liberally festooned with Spanish moss. There are plenty of fine large, dead and rotting tree stumps. There is the same high humidity and temperature and deep shade conditions. There is, in fact, a reasonable facsimile of the conditions of those Himalayan and Burmese jungle valleys. I would very much like to try to establish a system of growing these superb plant. To assist in this, Tom Spring-Smythe will, I hope, be sending me seeds and I am now busy collecting native American seeds with which to establish an equitable swap system with the many willing growers in Great Britain. As I said, though, what the area needs is a proper botanical garden where the thing can be done on a proper and scientific basis-the findings being passed on to private gardeners and to the trade.
Eastwards along the Burma, India, China frontier area, one is deep in Rhododendron-land and the species abound. Here one sees groves of the multi-colored Triflorum series, the big leaved Grande and Falconeri series just about all the rhododendrons man could desire.
One thing remains constant throughout the entire area. This is the root conditions enjoyed by the plants. The soil of the Gulf Coast area is, as you well know, sedimentary. It is, as far as I am able to discover, and to the limit of my experience which is very small, an area of land laid down by the deposit of silt from the Mississippi river, its tributary or contributory rivers. The soil particles are fine, they pack almost to the point of imperviability to both air and water. When wet, they retain a great deal too much stagnant water. When dry, they set like a brick. Neither condition is desirable to rhododendrons. In nature we saw them growing on high rocky plateaus, on steep mountains, in folds in the hills, on alpine meadows, wooded hills, on the lower slopes, then finally as epiphytes in the valley bottoms. Everywhere they enjoy primarily perfect drainage. Cold, heat, wind, drought, sun or shade they will endure. Stagnant water at the roots, they will not. Mr. Coyle will be telling you, as he has already done through his news letters, the best methods of planting and growing under Gulf Coast conditions, and I can fully vouch for the wisdom of these ways.
I believe quite firmly that once we can provide suitable soil conditions, either by adapting existing soil or by growing on raised beds, many other troubles will, if not disappear, certainly diminish. The latitude of both areas is roughly the same; the weather conditions somewhat similar. The opportunity is ours.
Returning to Britain for a few minutes, I would like briefly to examine some of the gardens I have known, have visited or worked in, where rhododendrons have been the feature plants. On the west coast of Scotland are such famous gardens as Glenarn, Inverewe, Brodick and Lochinch Castles. All of these gardens enjoy a temperate climate, warmed by the gulf stream and plentifully supplied with Atlantic moisture. They also all have either good slopes or light soils. The same applies to the gardens situated within the Cornish, Devonshire peninsula. There is always a warm atmosphere and well drained soil.
My own home county, Sussex, is in the south of England but there we come a little more under the influence of the continental weather. Colder winters, slightly dryer summers. Stonehurst, one of the gardens I worked, lay across a steep valley. The soil was heavy Weald clay overlaid by Tunbridge Wells greensand. A huge seam of rocks outcropped through the estate and rhododendrons grew almost like weeds. R. ponticum had in fact become quite a problem to our commercial forests, it being such an expensive weed to control till the trees can out-grow it. We also found plants of the Triflorum, Fortunei, Thomsonii, series growing wild, as well as hybrids of R. griersonianum, and other series.
The garden varied from the deep shade of the woodland gardens where we had a vast collection of species and hybrids, to the harshly exposed rock gardens and lawns where we grew hardy hybrids, Exbury strain azaleas, Kurume azaleas and miniature rock garden species and their hybrids.
Exbury, the headquarters, at one time, of rhododendron growing, is situated on the shores of the Solent and Southampton water. Sheltered from the north by the New Forest and from the south gales by the Isle of Wight, the soil is a shallow and rather poor, sandy loam overlaying many feet of gravel. Even in moderate summers, watering was a major problem. Mulching with peat or bracken did much to alleviate this condition. Humus material in the form of peat, leaf-mold, bracken, even straw, was worked into the nurseries in copious quantities to further combat drought.
Leonardslee, the garden of Sir Giles Loder and home of the world famous Loderi hybrids, is a garden rather similar to Stonehurst-a deep valley, lakes at the bottom, rhododendrons and other flowering trees and shrubs growing on the hillsides.
Sheffield Park is an entirely different proposition. Here one is on relatively flat ground, the soil heavy, almost impervious clay. Lord Sheffield, the originator of the gardens, and later The Honorable Christopher Soames put a great deal of labor into double digging as much as possible of the gardens, certainly all new plantings. Again copious quantities of humus material were worked in to improve the soil structure and to improve drainage. Some of the big Loderi's and auriculatums are now 15 to 20 feet high so you see, even heavy clay can be worked and made to grow good rhododendrons.
Rhododendrons in Britain provide not only a solid backbone of landscaping, but also they are one of the more colorful shrubs over a long period of the year. In mild winters we begin with 'Nobleanum Coccineum', which I have used to decorate the Christmas table, through 'Praecox', lutescens to 'Shilsoni' then on through the main crop of species and hybrids. Later in August we get R. auriculatum and its hybrids and occasionally, the very late and rather infrequent flowering R. serotinum.
Here in the Gulf area I would like to try the Triflorum series and I believe the Maddennii and Edgeworthii's also should be important. R. griersonianum itself we found incompletely hardy in the cooler parts of Great Britain, but it should do well in the south--being reputedly sun hardy. It and its hybrids could be used to good effect. The closer you keep to the species, griersonianum, the nearer to epiphyte conditions you can give it. I would like to try the Thomsonii series, but feel they will need deep shade here. Perhaps the higher altitude sub-series Campylocarpum, or Selense might stand the bright sunshine.
Of the rock garden gems, this is not so difficult as one might think. These are generally extremely hardy plants both to sunshine and to cold. It would be most interesting to build a rock garden devoted to these plants.
Before leaving you I would just like to explain that in these notes I have referred mainly to species. This is not through any preference on my part but merely that where one can establish species, there one should also be able to grow its hybrids. Here in America, as everywhere, there is so much to learn about the rhododendron. As a race of plants, they are here, in their infancy, gaining popularity so fast that I can readily see that they will in time take pride of place over the camellia. This, to us all, is extremely important. Commercially it means very big business. Academically, students will want to study growing plants in order to produce, through industry, the types of trouble controls and growth stimulants we need. Artistically, landscape students will need to see plants growing in order to assess their usability in their future works. And we gardeners just want to know what we can use, where and how.
Ladies and gentlemen, we are on the threshold of a fantastically exciting era, almost at the birth of a new plant, and it is we who can do much to insure the growth in popularity and future of this wonderful genus, the Rhododendron.