Rhododendrons in Britain
Reprinted from the New Zealand Rhododendron Association Inc., November, 1952
Rhododendrons in England during the early spring of this year suffered quite a lot in the months of March and April through a succession of frosts, which although not very severe in their intensity were quite hard enough to spoil many of the semi-tender ones grown out of doors. I unfortunately was unable to visit some of the better known gardens in the South of England until later in the year, and so missed seeing what must be a wonderful feast of colour to not only rhododendron enthusiasts, but to all who have an interest in flowering shrubs.
The indoor grown ones however at Kew and Wisley and other places naturally did not suffer from frost damage and were able to give me an indication of what some of the early ones would be like when they are grown in a frost free position, or when the seasons are more favorable.
At Kew one of the large leafed varieties, Rhododendron macabeanum was very fine and this species should do very well in many situations in New Zealand, a very fine one is growing at Ilam. It has a lovely truss of creamy yellow flowers which show to advantage on the large dark green leaves. It, however, would be rather slow in flowering and anyone who grows it from seed would need a lot of patience before it would come to perfection.
Another attractive species which is grown with comparative success in Great Britain is Rhododendron leucaspis; this is a small flat-growing kind with roundish leaves and for its size large white and in some cases pink flowers. The foliage of this plant is a silvery shade not unlike R. bullatum, which is an added attraction. It is a little tender in outdoor situations, but will be worth cultivating in New Zealand where frosts are not too severe. There were a number of Javanese hybrids in flower in some of the temperate houses at Kew which had rather small flowers of different shades, from white to pink and salmon colour and also a shade of scarlet. These plants would only be suitable for hothouse cultivation, except in very favorable conditions in the North Island.
A Rhododendron veitchianum with much larger white flowers than any previously seen was also in full bloom at Kew and this variety I am sure would be hardy enough to grow out of doors with us. The shape and the size of its flowers are one of its chief attractions, the petals being large and detached from each other are not unlike our native Clematis in form.
Of the hybrids which flower in the early spring, one called R. 'Burmaureum' burmanicum (Aureum cross) had very fine flowers of a deep yellow shade and the indications were that, although somewhat tender, it would be more hardy than either of the parents. This contention has been proved by some of the experts in England and is another reason for continuing with the hybridizing of the species. The Cross R. Bullatum x R. Ciliicalyx also produced a mass of lovely white flowers which made a very fine show. The indoor grown rhododendrons seem to lack the scent which is such a feature of some of the varieties above mentioned, when grown in out of doors conditions; in fact most plants which are noted for their scent do not seem to have nearly as much as those grown in New Zealand; this was very noticeable in Magnolias at Kew. The frequent showers and less sunshine may be responsible for this difference.
The Rock Garden at Kew has many of the smaller leafed varieties of rhododendrons growing very well, but here again many of the early ones were badly affected by the numerous spring frosts. One, however, which appeared to escape this damage was Rhododendron scintillans which had flowers of a deep bluefish-purple shade was remarkable for its hardiness when other kinds were so very badly cut. Kew gardens are not subject to very severe frost as a rule when compared with other places and I was surprised later on in the year to see a wonderful 'Paulonia' in full bloom. One man who goes every year to see this particular tree said it was the best flowering year he had ever seen for this specimen. Later on in the season the Rhododendron Dell in the gardens which had masses of the older hardy hybrids, made a wonderful show and I think surpasses in beauty any other kind of shrub in this world wide collection of trees and plants. There were a number of the newer and more showy hybrids plants out in places, but they were too young to be shown to perfection, and in a great number of cases were planted too close together and would need to be transplanted in the near future for each bush to be shown to best advantage.
I was able to visit the R. H. Society's gardens at Wisley on several occasions and saw a number of tender varieties growing under glass; also in a shady corner of the grounds many very fine specimens of R. thomsonii showed to perfection with the sun shining through high overhead shade. Numbers of flowers, however, were frosted rather spoiling the general effect. These older rhododendrons were growing in a fairly damp situation and underneath were numerous flowering bulbs and woodland plants which seemed to grow so naturally, and fitted in well with the general scheme of things.
Immediately above this area a Rock Garden has been formed which had innumerable treasures for a horticulturist including many of the dwarf and alpine rhododendrons, but the main planting of them was on a small hill with a few Scots pines growing on it giving the necessary high shade. This situation will in time become one of the most noted rhododendron gardens in England. The plants are nearly all the new species which are classified into their various sections and also most of the newer hybrids. There is one drawback to this site, however, that the soil is rather light and the rainfall is not quite adequate to ensure full growth; but as water is laid on by means of pipes over the whole area, watering can be done during dry seasons. Besides rhododendrons which range from the most dwarf-like alpine species to the giants of the race, there are large plots of Azaleas planted in more open space giving a wonderful blaze of colour when seen in the fleeting sunshine which is such a feature of the weather in most parts of England.
It was not till later on in the season that I was privileged to see some of the private gardens which are famous for their collections of rhododendrons and azaleas, but unfortunately it was rather late in the season to see them at their best. Among those which I visited in the South of England were Exbury, Mr. L. de Rothschild's, near Southampton, Leonardslee, Sir Giles Loder's place and home of the famous Loderi group, Wakehurst also in Sussex and the home of the late Lord Wakehurst, who, as Mr. G. W. E. Loder donated the Loder Cup to New Zealand; also another young but what will be a famous collection at Windsor Great Great Park, and Mrs. Stevenson's Towers Court with the most extensive planting of species in Britain. All these places have acres and acres of rhododendrons and azaleas which are mostly growing on low hills with valleys in between and generally have unlimited scope for expansion. As they are among trees and shrubs with lovely walks all through the grounds the full beauty of these plants can be enjoyed. Most of the Estates are open to the public on certain days of the year when large numbers of people visit and enjoy the beauties of the grounds and gardens. It would take up too much time and space to enumerate all the different kinds of rhododendrons to be seen in each place, but it was interesting to compare them with those growing in New Zealand. There are, of course, very many more species and hybrids than we will ever have and the tendency seems to favour the smaller varieties which will stand up to the weather. There seems to be a great liking for the yellow and orange varieties and much of the hybridizing of these species has taken place during the last few years. At the same time it will be hard to beat the pure yellow species which are so attractive when they reach the full flowering stage. The Horticultural Shows in London gave me a chance to see the best blooms that can be produced and I attended quite a number where in a few hours can be seen exhibits which would take weeks and weeks to study in their natural sites. Of course, there is no comparison between a single bloom shown in a vase and a bush in a garden covered with bloom. At most of the shows rhododendrons are exhibited complete with foliage and made up in such a natural setting that a very good indication can be formed of what they look like in the garden localities. While the R. H. S. holds shows every fortnight during the Spring, Summer and Autumn months at Vincent Square in London, the thrill of the year is the Chelsea Show which has to be seen to be appreciated; when it is realized that this year the main marquee covered an area of three and a half acres and the outside exhibits extended over the same acreage or more, some idea of the extent of the show can be gathered. When first entering the large tent the effect on the visitor is one of bewilderment at its immensity; and to see everything at all carefully two or three days must be spent there. At the end of the third day most of the flowers were still quite fresh and as natural as they were in the beginning, showing what a lot of trouble and expense the exhibitors go to to make their sections attractive. Some of the rhododendrons were plants of up to ten feet in height in full flower and others were laid out between pathways with Blue Poppies, Primulas and many other woodland plants growing amongst them. Much care and attention has to be taken to retard or advance the blooming period of many kinds of flowers to bring them to perfection at the time of the shows. Competitors come from all over Britain and it is a great achievement to get prizes where there are so many and varied classes.
England as a whole is suitable for the growth and cultivation of the rhododendron species, especially in the southern and western districts but it is necessary to visit Scotland to see them growing to perfection. In eastern districts the colder conditions make the choice of kinds rather narrower than the west, where abundant rainfall and comparative lack of severe spring frosts allows them to thrive in a most luxuriant fashion. It was interesting to note that the flowering of the main crop of rhododendron in the Edinburgh Botanical Gardens was comparatively good in comparison to that of Southern England, caused no doubt by the later flowering period when frosts were comparatively light.
These gardens are very extensive and include a large rockery where many of the alpine varieties are doing excellently under what must be very bleak and windy conditions throughout most of the year. A number of New Zealand plants were grown in the same area and our Mountain Lily, Ranuculus lyahi, was in flower during my visit, as well as Celmisias and other plants.
The main planting of rhododendrons, however, was on a slight slope which was planted with low growing coniferous trees and during a later visit the Meconopsis species were in full bloom, which was a sight to be remembered. The dappled sunlight shining on the beautiful peacock-blue flowers had a wonderful effect and quite made up for the lack of flowers on the rhododendrons which had bloomed earlier in the year. During my visit to Scotland in August I had an opportunity of visiting some of the most noted rhododendron collections in West Scotland and here undoubtedly a true indication of the value of these wonderful plants can be appreciated. Amongst the places visited were Stonefield, Succoth, Lochinch, Logan and the Isle of Arran. There are many other places where rhododendrons do equally well, but distances did not enable me to spend more time in visiting them. The planting at Stonefield which is now a private hotel, had been done many years ago, but there were no reliable records of the actual years and source of supplies of species, but there must have been importation of seeds from earliest plant hunters' expeditions. Some of the kinds were of tree size, one individual trunk of an arboreum being over six feet in circumference, and another which had several leaders came in the aggregate to over ten feet in girth. These arboreum varieties, although estimated to be over 100 years old and in cases were more than forty feet in height, were still in perfect health and produced fine crops of flowers in most seasons. This point about the general health and robustness of species at a great age must be considered when a comparison with hybrids is made. In some cases in England I saw hybrids which were not nearly as old and had grown into leggy and unattractive looking plants, which did not display their flowers to advantage. It was interesting at Stonefield to see the large leafed varieties growing naturally from seed. This regeneration is taking place in other sites and on the Isle of Arran, the Duke of Montrose told me that the common ponticum was spreading very rapidly on his hill country and that it was costing him up to £14 an acre to clear them. The large leafed sorts were also growing from seed on Arran and the climate of West Scotland seems to be ideal for this purpose. The general layout of the rhododendron areas is under wide spaced trees and in most cases on hilly and undulating country, this usually gives a certain amount of shelter from frost and enables the owners to select sites suitable for the various varieties. At Brodick Castle this was very noticeable, large and extensive growths of Ponticum were utilized for shelter and good sorts, mostly species, had then been introduced in corners and bays and the general effect was most pleasing. Some of the R. sinogrande on this estate had leaves at least three feet in length and R. giganteums were comparatively hardy and were also being reproduced from seed. Many of these Scottish gardens are situated at sea level and do not appear to suffer from the salt air except where winds are frequent and of strong force. In one instance at a place called Inverewe which is slightly north-west of Inverness a wonderful collection of rhododendrons has been grown, only after shelter had been provided by trees and Ponticum rhododendrons. These latter are now spreading naturally and the owner regrets that they were originally used for shelter purposes. These gardens on the West Coast of Scotland are no doubt eminently suited to the culture of rhododendrons on account of the mild conditions caused by the Gulf Stream, also the abundant rainfall which is similar to that of the West Coast in New Zealand. At Inverewe plants and shrubs which are half-hardy in Cornwall and Devon flourish, and many New Zealand species are doing well including the Catham Island Lily which has flowered and is growing freely from seed. In the South western countries of Scotland also, some very fine gardens are to be found. Lochinch, the Earl of Stair's property has many acres planted with masses of rhododendrons and azaleas. Logan which is also near the latter place and belongs to Mr. Hambro has a great assortment of species and hybrids as well as many New Zealand shrubs including a Southern Rata which has flowered frequently and seems to enjoy the climate.
The last place of note which I visited was Bodnant, Lord Aberconway's place near Colwyn Bay in North Wales. Unfortunately the day of my visit was wet and the tour of the gardens had to be cut short and it was not possible to see all the wonderful collection of plants and trees which had been gathered together at this famous place. It enjoys a fairly abundant rainfall though not quite as heavy as further north in Scotland but the temperatures are fairly uniform throughout the year and as there is plenty of tree shelter, frosts do no? cause a great deal of damage. The layout of this property is very fine. In front of the house and facing south are terraced gardens which have all kinds of plants, shrubs and trees, some of which bloom throughout most of the year. During my call there in August, the Aucryphias were at their best and what a wonderful show they made. Further on in this place a stream flows through a valley which has small ponds and dams in it as well as some magnificent conifers. The valley has all kinds of rhododendrons and azaleas growing on both sides and in the spring when they are in flower must be a wonderful sight. These extensive gardens have such opportunities for planting that the various kinds of rhododendrons can be selected and planted in the most suitable spots. Gardens such as Bodnant must be a paradise for a landscape gardener who has time to study and plan on a similar scale. After seeing the various places and gardens which I did during my visit to Britain and realizing that there were many hundreds of equally suitable places for the culture of rhododendron series, I am more than ever enamored of their value and suitability for cultivation in New Zealand. To my mind there is no other shrub or plant that can compare with them for variety and colour. It is also evident when seeing the size to which they attain that woodland conditions are more suited to their growth than gardens. At the same time the Alpine varieties can be grown in very small plots and a most attractive blending of colours can be obtained by this means.
Taking it on the whole it seems that the British climate is generally more suitable than New Zealand, but that many of the more tender varieties have a better chance of survival in New Zealand, the incidence of frost in England being the main factor to be guarded against. Many years may go by without any exceptionally cold temperatures being experienced, then a particularly cold spell may do very great damage especially in the warmer, moister situations. The weather conditions are more regular than those in New Zealand.