Notes on the Cinnabarinum Series
By Alleyne Cook, Vancouver, B.C.
It is a curious and rather unfortunate fact that a series so lovely and fascinating as the Cinnabarinum should be so neglected by rhododendron growers. In every way they are different from the general conception of a rhododendron. The flowers instead of being in a compact truss, hang in clusters of 5-8 flowers. These flowers are trumpet shaped, tubular for the first 2 inches, then flaring to 1½ inches wide at the mouth. The foliage is small, never more than 3 inches long, often pale blue when newly broken from the bud, usually blue green when mature. The underside of the foliage is spotted with brown scales. The habit of growth is thinner, upright, springing in many stems from the base, and if a little pruning is not undertaken the bush will become lanky. Under normal climatic conditions, and provided they are given a protected location, they are hardy along all the West Coast. When in growth and in full bloom there are no more desirable rhododendrons to be had.
In areas where there is a low humidity, rhododendrons with normal leaves tend to suffer, while those with big leaves find conditions intolerable. It is here that the Cinnabarinum series, along with the Triflorum series will grow well. An example of this was in the garden of Capt. C. Ingram in Kent, England. The degree of humidity in that county is lower than in other parts of England. The biting cold wind - always a menace with big leaved plants, blows down from the north. These conditions do not seem to effect either of these series, and the numerous species grow well in the semi-shade of the cherries for which his garden is famous.
R. cinnabarinum grows in the Himalayas between 10,000 and 12,000 feet. The first seed was sent to England by Sir J. Hooker in 1850. Several years later small plants flowered in the Sunningdale Nurseries, and it is quite probable that a number of the very old specimens found in England came from that batch of seedlings.
One ancient specimen, 10 ft. high and 20 ft. in diameter, still flourishes in that nursery. It grows in the open, where the occasional early frost can prune any soft growth. In May when in full flower it covers itself with thousands of rosy red trumpets, hanging against a background of blue-green foliage.
The color and shape of these flowers are usually compared to the tender climbing Lapageria rosea. Whoever made the comparison must have been looking at a very starved Lapageria, for although of similar color, this gorgeous climber, a member of the lily family, and the national flower of Chile, is larger and far more beautiful.
This is not the only large specimen in England, we have seen a taller plant at Muncaster Castle in N.W. England, while at Stonefield Castle, that Mecca of ancient rhododendrons, there are plants of the same age and equal size. There are without a doubt many other gardens with equally large plants. R. cinnabarinum is a variable species. Several different varieties are recognized.
The favorite, with its deeper red flowers is var. roylei. Toned down by a waxy bloom, the color is not the intense scarlet seen in so many of the better known species. As with R. cinnabarinum, the blue green foliage forms an excellent background, giving the bush that extra garden merit in the off-season. This variety was also introduced in 1850 by Hooker, and an original plant still survives in the Sunningdale Nurseries.
It is however growing in a much more sheltered location with a considerable amount of overhead coverage. Here it has made a loose straggling bush, and is not particularly free flowering.
Comparing it with the previously mentioned 'type' growing in the open, it would seem that the species does better, grows into a more shapely bush, and flowers more freely, when planted in an open location. Whether or not this condition applies only to this Nursery, where the rainfall is 35 inches, hard frosts are expected every winter, and the summer heat is not great, we do not know. Growers with different aspects will probably have to shift their plants until the optimum conditions are obtained.
Advice is always given by garden writers to plant R. var. roylei so that the evening sun can shine through the flowers and light them up. Certainly good advice, for no flower glows with more intensity under these conditions. But in how many gardens is there a location where this can be done? Not very many.
Of all the varieties of R. cinnabarinum the variety blandfordiaeflorum appears to be able to withstand the greatest degree of cold. In the '55 freeze, a condition so unusual that it should be ignored, plants of it were cut to the ground but the following year they shot away again. All the others were completely killed.
The flowers of R. var. blandfordiaeflorum are an unusual combination of colors; shades of red on the outside, and yellow or apricot inside.
At Wisley there is a splendid specimen and Mr. Hanger writing in the "Rhododendron Year Book" states that it is one of his five favorite species.
Mr. Cox in his excellent book "Modern Rhododendrons" writes about two other varieties, var. purpurellum, with rich plum-purple flowers, and var. pallidum, with flowers of mauve-pink. We have never seen these and know nothing about them.
The Sunningdale Nurseries list another, var. darjeeling, this we also know nothing about but hope to, if our imported plant survives the journey from England.
R. concatenans was discovered by Ward in 1924. The flowers are bell shaped, apricot in color, and in trusses of 4-7. The new growth is a soft blue, the mature foliage a green-blue. It is not supposed to be as hardy as R. cinnabarinum.
If this is correct (the R. H. S. Handbook give both H-3 rating) its powers of shooting from the base when the main stems die or are killed back, are equal to R. cinnabarinum.
A large plant, shifted from the Tower Court garden to the Sunningdale Nurseries died steadily back, either from the effect of the shift, the dryness of the following summer, or because the nursery is in a colder location. As fast as an old branch died, shoots sprang from the base, until the original bush was replaced by new growth.
The main planting of R. concatenans at Tower Court is on the east slope in front of the old house. In appearance they are loose bushes about 5 feet high and 5-7 feet through. Before digging, plants this diameter had to be reduced. Such was the habit of growth-many stems from the base rather than one main trunk, that the 5-7 feet could be drawn into a comfortable two.
In the former condition it was impossible to get under the plants and dig around the roots, in the latter it was a simple operation.
R. xanthocodon was found by Ward in Tibet, where it grows at 12,000 feet. The flowers, when compared with R. concatenans, are nearer to true yellow, are smaller in size, and are less numerous in the truss. The foliage is a grey-green shade. The habit of growth of plants we have seen is more upright leaving a bare open base to the bush. This results in the flowers being on the top of the shrub rather than covering it. It is considered by some people that R. xanthocodon and R. concatenans are the same plant, and at a later date when time allows more study of the mature plants of the series a definite conclusion can be given.
Last in the series is R. keysii. It can be placed in the oddity clause. It grows about 10 feet high and has a leggy habit. The flowers are completely tubular, about one inch long, bright waxy red tipped with yellow.
All of these species and varieties with the exception of R. keysii are well worth growing for a free flowering bush is a joy to behold. For those people who do not desire to wait the extra time that a species takes to flower there is an outstanding range of hybrids. It is only natural that flowers with such richness of color and firmness of texture should be used extensively for hybridizing.
The first cross to be made was between the red R. cinnabarinum and the faintly pink R. maddenii. The former had small flowers and is hardy, the latter large flowers and tender. The result was the magnificent R. 'Royal Flush'. There are two recognized forms; R. 'Royal Flush' yellow, with bells variously described as buff yellow or cream flushed yellow, and R. 'Royal Flush' pink, the flowers of which are salmon pink flushed orange. These flowers are 4 inches long and are 2½ inches across at the mouth.
Small plants have a rather untidy loose habit but the large ones we saw at Trewithen in Cornwall had grown thick enough to form a hedge. It was unfortunate that they were not in flower at the time of our visit for they must have been a magnificent sight when in full bloom.
Fig. 21. R. 'Lady Roseberry'
R. Henny photo
The hybrids for which Lionel de Rothschild is probably best known, at least in England, are his R. 'Lady Chamberlain's (Fig. 22) and R. 'Lady Roseberry's. (Fig. 21). These form the Lady Chamberlain walk at Exbury, described by many writers as magnificent. It is in fact an overgrown mess. It was, when we left England, impossible to see more than two or three plants at a time, and to stand at one end to compare the various seedlings or to admire their wonderful loveliness was impossible. On each side of the path are small trees up to 8 feet high, in the spring laden down under the weight of hundreds of flowers in shades of orange, salmon, or pink.
Fig. 22. R. 'Lady Chamberlain'
R. Henny photo
The foliage is glaucous, the young breaking growth nearer to blue. This, breaking amid the flowers adds to the quality of the bush.
Lionel de Rothschild crossed the yellow form of R. 'Royal Flush' with the brilliant red R. cinnabarinum roylei the resultant seedlings becoming R. 'Lady Chamberlain'. In each truss there are from 6-8 pendulous flowers, each fully 3 inches long and 2 inches wide at the mouth. In 1931 one seedling received a First Class Certificate.
Since then many varieties have been named, the following being found after looking through several publications. It will be noted that people's ideas of a color can vary considerably.
R. 'Lady Chamberlain' F.C.C.-deep salmon orange, apricot pink, yellow overlaid salmon orange, hanging terracotta to orange Lapageria-like flowers.
Var. 'Apricot' orange-pink, describes itself.
Var. 'Chelsea', orange-pink.
Var. 'Coral King', yellow overlaid salmon-orange.
Var. 'Coronation', no description. Var. 'Exbury', yellow overlaid salmon-orange.
Var. 'Gleam', crimson tipped orange yellow.
Var. 'Golden Queen' F.C.C., waxy tubular flowers which are a soft salmon pink shading to orange, golden orange trumpets deeply flushed red.
Var. 'Ivy' - No description.
Var. 'Oriflame', orange-red.
Var. 'Salmon Trout', vivid salmon, exactly the color of a freshly cooked salmon. (This is rather confusing, cooked salmon can vary from white through to red depending on the species of salmon).
Var. 'Bodnant Yellow', this was raised by Lord Aberconway and is no longer listed as a variety of R. 'Lady Chamberlain'. In color it is orange-buff with a deeper reddish flush outside.
It must be admitted that when one color overlays another the combination is much harder to describe.
At the same time Lionel de Rothschild crossed the pink form of R. 'Royal Flush' with R. cinnabarinum var. roylei. The seedlings were called R. 'Lady Roseberry', and in these pink is the predominate color.
The following are the varieties that have been named;
R. 'Lady Roseberry' F.C.C., lovely deep rose, is rich salmon pink, soft rose-pink overlaid and carmine.
Var. 'Dalneny', soft satiny pink.
Var. 'Etna', bright satiny pink.
Var. 'Pink Beauty', no description.
Var. 'Pink Delight', no description.
The only difference between the two plants is that the various varieties of 'Lady Chamberlain' vary from apricot through orange-yellow to orange-red, while 'Lady Roseberry' are rose to pink. Both are May flowering and will come out together.
As far as the States are concerned, all these various varieties of R. 'Lady Chamberlain' and R. 'Lady Roseberry' do not lead to very much confusion. They are not popular plants. They are not what the average gardener imagines a rhododendron should be like; he naturally thinks of a blob such as R. 'Pink Pearl'. They are slower flowering than the hardy hybrids, and as the nurseryman has to hold them longer before they are ready for sale he avoids them completely. Their vigor and habit of growth are also different, while their hardiness is in doubt.
It shouldn't be. In a normal winter for Vancouver when the temperature went down to 10° and the ground was frozen solid, small plants in Len Living's Nursery came through without either bark-split or foliage damage. What is even more curious, is the way the Royston Nurseries find that R. 'Royal Flush' can stand greater cold than either 'Lady Chamberlain', or 'Lady Roseberry', and of the three R. 'Lady Chamberlain' is the first to suffer.
It would seem that the hybrids are like the species, keeping a better shape and flowering more freely if grown in the open, rather than in the shade. A plant of R. 'Lady Roseberry' at Leonardslee in a more exposed position than those at Exbury was carrying more flowers than we have seen on any bush with the exception of R. 'Yellow Hammer.' (Fig. 24)
Because there is such a small demand, and because there is no way of checking, anything orange can be any variety of R. 'Lady Chamberlain,' and anything pink can be a R. 'Lady Roseberry'. The results will always be beautiful.
There are several other hybrids all of which have R. cinnabarinum roylei as a parent. All of them look very much alike.
R. 'Perseverance' is a cross using R. 'Lady Chamberlain' as the other parent. The raiser was probably trying to get a new hybrid that was reliable in his area with regards to hardiness. What he got looks like a R. roylei.
R. ambiguum is a hardy member of the triflorum series, and when crossed with R. var. roylei, the result is R. 'Biskra.' It looks like a pale R. 'Lady Roseberry.' There is a large plant in the Savile Gardens in Windsor Great Park, it is sheltered on all sides but is open above, and every year it is loaded with flowers.
The second parent of R. 'Conroy' is R. concatenans. The flowers are called light orange, but the plants we have seen, although fairly large were not very floriferous.
R. concatenans, R. maddenii, and R. cinnabarinum var. blandfordiaeflorum were all used in the raising of R. 'Trewithen Orange.' As would be expected, orange is the predominant shade, the cover of the 1951 Rhodo. Year Book giving a good illustration of it. That one is not the only form of it. In the previously mentioned garden in Kent we saw a pink rhododendron with hanging tubular-flowers. The name Mr. Ingram gave it was R. 'Royal Flush' so we concluded that there had been variations from pink to orange among the seedlings. This hybrid is not available commercially.
Fig. 23. R. 'Lady Berry'
R. Henny photo
Another, so similar to R. 'Lady Roseberry' that it needs a label to differentiate between them is R. 'Lady Berry'. (Fig. 23) It was not until the second attempt that it was given the exalted rank of F.C.C. so we may conclude that at that meeting someone was scratching someone else's back.
Fig. 24. R. 'Yellow Hammer'
R. Henny photo
Any of these hybrids, if available, are worthy of a place in the garden. The soil conditions they need are no different from any other rhododendron. The colder the climate, the harder they should be grown, and a more sheltered location in the garden given to them. Then when they are old enough to flower freely they will become the pride of the garden.