JARS v39n3 - The Elegant Cinnabarinums

The Elegant Cinnabarinums
Felice Blake
Kallista, Vic, Australia

"The Royal Flushes and the Ladies seem to me to exude an air of sophisticated elegance" - so wrote the late A.T. Johnson in his delightful book The Mill Gaden when referring to these hybrids of R. cinnabarinum . In fact, of all the more unusual rhododendrons, the beautiful and so very different cinnabarinums must rank close to the top. This superb collection of plants, not so many species, but a host of hybrids with flowers likened to those of that lovely climber, the bell-flowered Lapageria , provide a fascination for those growers who look for something removed from the ordinary.
In the new rhododendron classification, the old Cinnabarinum Series, now Subsection Cinnabarina has been reduced by Dr. Cullen to merely two species - R. cinnabarinum and keysii , with R. xanthocodon being relegated to a subspecies of R. cinnabarinum , and the delectable R. concatenans being considered synonymous with R. xanthocodon , alas! alas! and the rare R. tamaense also now a subspecies of R. cinnabarinum . It seems to me, as usual, being a mere gardener, that there is an ever-widening chasm between horticulturists and botanists. And then again it does seem that even the botanists cannot always agree among themselves! When one consults Mr. Davidian's The Rhododendron Species Vol. 1 Lepidotes , we find that R. concatenans , xanthocodon and tamaense have retained their specific status. And if we hark back to The Species of Rhododendron (J.B. Stevenson Ed.) we find that R. cinnabarinum , concatenans , igneum (now synonymous with R. keysii ), and keysii are listed, but not R. xanthocodon and tamaense . R. xanthocodon was only first described by Hutchinson in 1934 from a plant raised from Kingdon-Ward seed, whilst R. tamaense was discovered by Kingdon-Ward in North Burma in 1953, and described by Davidian in 1972. So whether or not we agree with alterations to rhododendron classification, we certainly need to keep abreast of today's thinking. But we still find rhododendron growers who cannot look past Stevenson, despite the half century that has passed since The Species of Rhododendron was first published, and the innumerable new discoveries since that time!
In the wild these lively rhododendrons range along the Himalayas from Nepal, India (West Bengal and Arunachal Pradesh), Sikkim, Bhutan, the Chinese province of Xizang (Tibet) to North Burma. The cinnabarinums are lepidotes, with scaly leaves, evergreen with the exception of R. tamaense which is apparently deciduous or semi-deciduous. The plants can vary in size usually from one to three metres, but up to seven metres, and the leaves are generally glaucous to a more or lesser degree. The type plant, R. cinnabarinum , was first introduced by Hooker from Sikkim in 1849, so this one has been around for a long time, and in this original collection the bell-shaped flowers were cinnabar red. As it has been collected many times from wide ranging areas, it has proved to be a most variable species and comes in a great variety of colours ranging from yellow, orange, pink, red and purple, and sometimes with a combination of colours as in var. blandfordiaeflorum . The leaves vary too, I have some small plants grown from seed from the A.G.S. Expedition to Sikkim in 1983 and the leaves on these are very glaucous, a really exceptional colour, which I hope will be retained when they grow bigger - finer colour than in the other forms of R. cinnabarinum which I grow. The flowers which are pendulous, are usually very waxen in appearance and contain copious nectar which is one of their most distinctive attributes. Unfortunately they can take some time to flower, so they are for the patient gardener! I must say, however, that one form I grow, a Nepal form, has flowered as a fairly small plant. R. concatenans , if we like to retain its specific status, is a charmer, with its glaucous foliage and lovely apricot blooms, making a rounded shrub. R. xanthocodon is a taller and narrower grower with yellow bells, and more olive green in its foliage. Most people would probably class R. keysii as something of a curiosity with its clusters of narrow tubular flowers, usually some shade of red with yellow lobes. However, as it grows larger it can be quite an attraction and is well worth growing.
Although personally I generally have a decided inclination towards species, like so many other growers, the various cinnabarinums have been used by the hybridists to such incredible effect, that I feel no garden should be without a reasonable representation, and who could really argue that point? In fact, I always consider the cinnabarinum hybrids as some of the most fascinating rhododendrons which one can grow, and they always invoke much comment from visitors to our garden. As the cinnabarinums and their hybrids are such a distinctive race, I feel that if possible a special area in the garden should be set aside for them so that they can be shown to their best advantage without unworthy competition from others in the genus. In my own garden my cinnabarinums are gown in a little glade quite removed from other rhododendrons, with windbreaks on the north and south sides, a boundary hedge on the west and one end of the house on the east side. Shade in varying degrees is provided by three very blue foliaged Cootamundra wattles ( Acacia baileyana ), two rowans ( Sorbus aucuparia and S. hupehensis ) and various maples ( Acer palmatum 'Linearilobum Atropurpureum', A. p. 'Senkaki', A saccharinum 'Pyramidale' and A. japonicum 'Vitifolium'), a cut leaf birch and a cut leaf alder to try and create a woodland setting. Around the year interest is accentuated by narcissus, hostas, epimediums, cyclamen, erythroniums, astibles and liliums, with a curving grass path bisecting the garden more or less from north to south.
I could not agree more with A.T. Johnson's comments about the "Royal Flushes and the Ladies"! The Royal Flushes are the result of mating R. cinnabarinum with R. maddenii , with the most charming results in flowers much larger than R. cinnabarinum in the most beautiful shades of pink, cream, yellow, orange and red, easily grown, flowering at a reasonable size, and fairly early in the season, and an absolute delight in any garden.

R. 'Royal Flush'  pink form
'Royal Flush' pink form
Photo by Felice Blake
R. 'Royal Flush'  yellow form
'Royal Flush' yellow form
Photo by Felice Blake

Then to add to the fascination R. cinnabarinum var. roylei (we do sometimes necessarily keep to the 'old' names for clarification) was crossed with the pink and orange forms of R. 'Royal Flush' to create the "Ladies" - the unusual and elegant R. 'Lady Chamberlain' in its various forms in a wide colour range from yellow to shades of salmon and orange, also R. 'Lady Roseberry' and its forms in shades of pink. Anyone enjoying these delicacies would feel they put lie to the oft heard remark that hybrids are "two good species spoilt." Most of the "Ladies" are too well known to require description which in any case can be found by consulting nurseries and books. My own particular favourite "Lady" is however of different parentage, being the child of R. 'Rosy Bell' x R. 'Royal Flush', that is R. 'Lady Berry', with its exquisite pink bells, deepening to red on the outside.

R. 'Lady Berry'
'Lady Berry'
Photo by Felice Blake

One of the more unusual hybrids with the most outstanding glaucous blue foliage is R. 'Oreocinn', and is the result of the marriage of R. oreotrephes with R. cinnabarinum . The foliage is even more distinctively blue than R. oreotrephes , and the flowers are a delicate violet. This is a particularly attractive garden plant retaining the beautiful foliage right throughout summer, and ranks high among the most desirable foliage plants.

R. 'Oreocinn' New Foliage
'Oreocinn' New Foliage
Photo by Felice Blake

One hybrid found in most gardens is the invaluable R. 'Alison Johnstone', with its pinky-amber flowers backed by glaucous foliage on a tight compact bush, being a cross between R. concatenans and R. yunnanense . Also very popular in my country is the eye-dazzling R. 'Trewithen Orange'. I was interested to read, and a little surprised, at the comments about R. 'Trewithen Orange' in Rhododendron News (the Portland Chapter publication) last March reporting that this rhododendron is not usually seen in the U.S. For the record, this plant was awarded the F.C.C. of the Royal Horticultural Society way back in 1950, so has been around for quite some time. R. 'Biskra' ( R. ambiguum x R. cinnabarinum var. roylei ) is another brilliant one, so too is R. 'Sirius' ( R. cinnabarinum var. roylei x R. crassum ). It is interesting to note that the various forms of cinnabarinums seem to be mainly mated with species and hybrids of Subsections Triflora and Maddenia, although one fascinating and almost incredibly sounding hybrid has for one parent R. flavidum (Subsection Lapponica) and R. 'Lady Rosebery' as the other. I have not yet been able to acquire this, but it is on the list of 'wanted' imports for some future time.
This covers only a mere handful of the plethora of cinnabarinum hybrids, and no doubt the interested enthusiast will seek out any available ones, or even try to create his own special hybrids - it does seem that there is endless scope in that field. I do grow more of these hybrids than I have mentioned so far, but have not yet flowered such ones as R. 'Bodnant Yellow', 'Cinncrass' and 'Conroy' - like a lot of hybrids these do take some time to flower. Another I have not yet mentioned is R. 'Cinnkeys', which takes after its parent R. keysii with its typical narrow tubular flowers, perhaps curious rather than glorious!
As the flowers in this group cover a very wide colour range, it can be prudent to take care in placement, as some can tend to clash, although I suppose it is a matter of personal preference, but I would not, for example, plant R. 'Lady Rosebery Pink Delight' next to R. 'Trewithen Orange'.
In the last few years I have noticed that curse, rhododendron rust ( Chrysomyxa ledi var. rhododendri ), has taken a liking to some of the cinnabarinums, in particular, R. cinnabarinum itself and the "Ladies". It is therefore necessary to keep a close watch on these plants during autumn and winter in particular, and to keep them regularly sprayed with systemic fungicide. This rust which was a rarity not so many years ago, has now become more prevalent in my country. Some growers would be inclined to discard any rhododendrons which are readily affected, but these cinnabarinums seem to me worth every effort to keep them in good health - the rewards in spring are sheer delight!