The Rhododendron Handbook, Part I, Rhododendron Species in General Cultivation
The Royal Horticultural Society, London, England, 1963
This is the latest edition of the series of handbooks appearing about every five years. Each edition sees certain changes and improvements, but none to date have seen nearly as many changes as those included in this edition.
Work on the classification of rhododendrons is going on almost continuously at the Royal Botanic Garden in Edinburgh and revisions of the various series have appeared from time to time in the Rhododendron Yearbook of the R. H. S. A number of these revisions have been incorporated in the present handbook so that many familiar species names have disappeared as they were merged with other species or eliminated as being duplicates of other previously named species. In this handbook, for instance, the Triflorum series is given as revised so that we no longer find such older well known species as R. exquisitum, chasmanthum, charianthum, timeteum, and others. As these revisions progress from time to time keys are developed to help in separating the various species. These are very useful and appear in increasing numbers in the list of rhododendrons in their series.
The descriptions of the various species have been greatly amplified and include the names of any superior clonal forms which have been named plus the names of various hybrids involving the species, provided such hybrids have received an award. In some cases, as with R. fortunei, this includes a rather large number of names of hybrids of which one parent is this species.
Another innovation is hardiness ratings and quality ratings somewhat similar to those given in the last American Rhododendron Society book. The hardiness ratings are based on 1 to 4 with a hardiness of 1 indicating a very tender species and 4 representing a species hardy anywhere in the British Isles. This is in reverse order to the system used by the American Rhododendron Society. Quality ratings are given for both flower and foliage characters, based again on four categories ranging from 4, which means excellent, to 1, which means of little merit.
The American Rhododendron Society, in its book Rhododendrons For Your Garden, was the first to publish separate ratings for flower and plant characters. It is interesting to note, however, that this idea had been developed independently by Dr. Fletcher of Edinburgh who discussed the matter at the International Conference in Portland shortly after the A.R.S. book was published. There is one important difference in that Dr. Fletcher commonly uses two ratings to show the range in a particular species, a system which has its merits. The A.R.S. system, on the other hand, gives one rating which indicates the quality of the best forms of the species. Although this book appears in the form of the previous handbooks it is completely new and everyone seriously interested in rhododendrons should have a copy. The revisions involved a tremendous amount of work for which Lord Aberconway, President of the R. H. S., in the Foreword, gives credit primarily to Dr. Harold Fletcher.
The Rhododendron and Camellia Yearbook, 1964, P. M. Synge and J. W. O. Platt, Editors, The Royal Horticultural Society, London, England, 1963, 156 pages
There are two features of these Yearbooks which make them required reading for the serious student of rhododendrons. One is the additions to the International Rhododendron Register. The activity of rhododendron breeders throughout the world is indicated by the fact that ninety-nine new variety names are registered. Of these, forty-four are from American breeders.
Another feature of this and recent Yearbooks of this series is the review of rhododendrons in their series which occasionally involves merging of old names, or changes in the direction of accuracy and conformity with botanical nomenclature. In this volume the Auriculatum, Edgeworthii, Scabrifolium, and Virgatum series have been reviewed. R. griersonianum has been taken out of the Auriculatum series and placed in a series by itself, the Griersonianum series.
One of the enjoyable features of these Yearbooks has been descriptions of various estates where notable rhododendron plants or plantings are to he seen. In this number there is a good description by Patrick Synge of rhododendrons and azaleas at Coles in Hampshire. A contribution from New Zealand describes the present development of the Pukeiti Rhododendron Trust. This now involves some 153 acres with a lodge and extensive rhododendron plantings. It would seem that this might become the outstanding public rhododendron garden in the southern hemisphere.
Mr. Day Campbell, under the title "Giants of the West," gives a fascinating description of a number of the large growing and large leafed rhododendron species growing on the West Coast of Scotland. This relatively warm, damp climate seems especially suited to these species, many of which have now reached enormous size.
Mr. R. L. Shaw discusses "The Natural Regeneration of Rhododendrons Lit Benmore." The fact that the environment at the Younger Botanic Garden is especially well suited to this genus is indicated by the fact that many species self sow and the seedlings have been able to compete with the natural vegetation.
An important topic is considered by David Wright who writes on "The Grouping of Rhododendrons for Small and Medium Sized Gardens." Factors affecting grouping such as color and texture of foliage, and color of young growth in the spring are discussed, in addition to flower color. Suitable companion plants for various types of rhododendrons are considered.
" Extracts From Letters to a Cornish Gardener" are taken from correspondence with the late E. J. P. Magor who was a great rhododendron gardener during the peak period of introduction of rhododendron species from Asia by the great plant collectors. It was a time when species were being established from the plant material, seeds as well as specimens, sent in by the various collectors. The comments are interesting, sometimes humorous, and throw considerable light on the problems involved when this tremendous lot of rhododendron material was presented to the botanists for sorting out into species.
Mr. E. H. M. Cox discusses "Scented Foliage in Rhododendrons," a subject which should be given much more attention than it has received. Scented foliage in many cases is a valuable attribute of a species or variety, but one which the average gardener perhaps thinks little of, or he may even not be aware that attractive scents exist in the leaves of many rhododendron species.
Other items discussed are "Rhododendron Foliage and Frost," "Symposium of Winter Damage, 1962-63, to Evergreen Azaleas," and reports of the 1963 Rhododendron Show in London, and the Rhododendron Show in Glasgow.
There are a number of interesting Chapter's on various phases of Camellia culture and nomenclature. These may easily be ignored by the simon pure rhododendron gardener but I found considerable of interest in them. One criticism of American gardens might be that we tend to go all out for one particular group of plants rather than becoming acquainted with all good garden subjects. A few camellias, well located in gardens where the climate is suitable, will not hurt any rhododendron collection.