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Rhododendron: The Hybrids / Azalea Hybrids - Evergreen

Family

The hybrids in this group derive from species of the Obtusum subseries (subgenus Tsutsia), and are sometimes known as Japanese azaleas and aptly so, since the oldest of the hybrids arose in the gardens of Japan several centuries ago, and the parental species are mainly natives of Japan. The term ‘evergreen’ is not entirely apposite for these azaleas, for mostly the leaves produced at the beginning of the growing season – the so-called ‘spring leaves’ – are dropped in the autumn, and the winter furnishing consists of the later-formed ‘summer leaves’, which are mostly smaller and thicker than the early ones. The amount of leafage retained depends partly on the clone, partly on the climate and the season.

It is only since the beginning of this century that evergreen azaleas have been cultivated out-of-doors in Britain to any extent, and their present popularity is of quite recent date. The number now available in commerce is considerable, and hybrids bred in Europe and the United States now outnumber the old Japanese garden varieties. The hybrid evergreen azaleas as a whole do not lend themselves to a coherent system of classification, several of the groups recognised in modern works being really no more than miscellaneous assemblages of hybrids that happen to have been raised by the same breeder. But the Kurume azaleas form a well-marked group, and the Indian azaleas, although of diverse parentage, have a common history in that they were bred for indoor decoration.

Indian Azaleas

The first evergreen azalea to reach Europe was R. indicum, which was introduced to Holland in the 17th century and subsequently lost. Linnaeus, who knew it only from the figure in a Dutch work, gave it the name Azalea indica, which in gardens came to be used indiscriminately for all the evergreen azaleas then known. The first of these to become established in gardens was R. simsii, introduced to Britain about 1808, which is in fact closely allied to R. indicum and was identified with it by the botanists of the time. R. simsii is a native of China and tender in most forms. The evergreen azaleas that followed, although brought from Canton nurseries, were of Japanese origin. They were: the form of Mucronatum (q.v.) with white flowers, which was generally known as ‘Indica Alba’ and later as ‘Old White’, and is probably what is now grown as typical R. mucronatum. This came in 1819 and was followed by ‘Phoeniceum’ (q.v.) in 1824. By the mid-1830s William Smith of Norbiton had already raised seedlings or hybrids from these early introductions, which are said to have stimulated interest in the group. Finally, in the early 1830s several forms of R. indicum arrived, of which the sportive ‘Variegatum’ was probably the most important as a parent.

In the 1840s and 1850s these ‘Indian azaleas’, as they were then known, became popular plants for the greenhouse and for indoor decoration, ‘to adorn mansions at routs, balls, and other festive occasions’ (as a contemporary writer put it). Many new varieties were raised in nurseries and private gardens from seed of the original introductions, of which many were no doubt hybrids, either spontaneous or deliberately made. The peak of the flowering season was then early May, not much earlier than the natural flowering time of these plants. Forcing does not seem to have been practised much in Britain at that time, and there were at that time no azaleas that could be reliably forced into flower by Christmas (or earlier), as many of the modern race can be. One of the best forcers was, curiously enough, ‘Indica Alba’ – the R. mucronatum of present-day gardens – which quite late in the last century was still forced commercially as a cut-flower. Another used for the same purpose was ‘Fielder’s White’, probably a seedling of ‘Indica Alba’, which was raised at Enfield early in the 1840s, and continued to be grown, even on the Continent, long after the Belgian greenhouse azaleas had supplanted the other English varieties.

The old Indian azaleas bred in Britain have long since been lost here, but a few were imported to the USA soon after they entered commerce and are still grown there in the south-east. Among those listed by Lee are: ‘Fielder’s White’; Todman’s ‘Flag of Truce’ and ‘Prince of Orange’, raised in a garden by Clapham Common, London; and ‘Iveryana’, raised Ivery of Dorking (The Azalea Book (1958), pp. 201-5 and plates 44 and 46). These deserve to be reintroduced, if only for sentimental reasons, all having originated here more than a century ago.

Around 1860 the English Indian azaleas began to be eclipsed by the forerunners of the great race of Belgian Indians and by the 1880s had all but disappeared from lists of recommended varieties. The early history of these continental varieties is apparently unknown, but the breeders were presumably working on the same lines as the English nurserymen and using the same material. The new kinds that came into commerce in ever-increasing numbers after 1860 are thought to have been derived predominantly from R. simsii and to a lesser extent from R. scabrum (through ‘Phoeniceum’). There seems to be little doubt that a major part in their formation was played by the three forms of R. simsii which Robert Fortune found in a Shanghai nursery and sent to Standish and Noble in 1851. These were ‘Vittata’, ‘Vittata Punctata’, and ‘Bealii’, all with white flowers variously striped or flecked and the first two perhaps representing two forms of a single sportive clone. Whether Standish and Noble ever put these into commerce in Britain is not certain, but it is surely significant that they showed ‘Bealii’ in Paris in 1853, and that all three introductions were first figured, as early as 1854, in Belgian publications. By 1864 ‘Vittata Punctata’ had become the most used forcing variety in the Paris area, but in Britain their arrival seems to have passed almost unnoticed.

No doubt owing to the predominance of R. simsii in their ancestry, the modern greenhouse azaleas are tender and would not have called for mention here were it not that they have been used to some extent in the breeding of hardy sorts. The first to attempt this seems to have been William Carmichael, mentioned below under ‘Mrs Carmichael’. Crossing various greenhouse azaleas with ‘Amoenum’ he raised several hybrids which he hoped would found a new race to rival the hardy rhododendrons. Some proved to be indeed quite hardy, but ironically they were also found to be excellent forcers and were never much used for their intended purpose. In more recent times Indian azaleas were used in breeding by Lionel de Rothschild at Exbury and by B. Y. Morrison at Glenn Dale, USA. Some of the Japanese Satsuki azaleas also have Belgian Indica azaleas in their parentage.

Kurume Azaleas

This numerous race was bred at Kurume, an inland town in Kyushu, which is the southernmost of the four main islands of Japan. The ancestral forms, it is said, were brought early in the 19th century from sacred Mt Kirishima, and from them seedlings were raised and propagated by Motozo Sakamoto. On his death the collection passed to Kijiro Akashi, who developed the race and is said to have raised most of those in cultivation. The azaleas of Mt Kirishima, according to Wilson, are very variable in the size and persistence of their leaves, and also in their flowers, which ‘vary a little in size, in degree of fragrance and greatly in colour; the most common shades are rosy mauve to magenta, but salmon and salmon-red are plentiful; pink, scarlet and crimson are rather rare. Plants bearing white flowers are occasionally found’. The two species that grow on the mountain are R. kiusianum and R. kaempferi, and it is now thought that the polymorphism of the Kirishima azaleas is due to hybridisation between them. Some of the Kurume azaleas show the influence of R. kaempferi quite strongly, but others, especially those with white or pale pink flowers, are very different from authentic R. kiusianum as grown in this country, yet show no influence of R. kaempferi. There appears to be some other element in the race, and it is suggested that this may be R. sataense (see further on page 697).

In the 19th century Kurume was remote from the main horticultural centres, and its azaleas were scarcely known, even in Japan itself, but early in this century a few reached Europe through the Yokohama Nursery Company, and others were imported by Dutch nurserymen. Among these were two of the most famous: ‘Hinomayo’ and ‘Hinodegiri’. Apart from these, the Kurumes grown in Britain belong to the ‘Wilson Fifty’, so called because they were selected from Asahi’s collection by the great plant-collector E. H. Wilson when he visited Kurume in 1918. Two sets of these fifty varieties (out of the 250 then grown) were bought by him for the Arnold Arboretum, where they were propagated and further distributed. See further in: Rehder and Wilson, Monograph of Azaleas (1921), pp. 34-8; Wilson, Plant Hunting, Vol. II, Chap. XLIX; Lee, The Azalea Book (1958), pp. 136-42. Wilson gave English names to his Fifty, which are not translations from the Japanese but invented by him. They are rarely used, the Japanese names being more memorable, even if difficult to pronounce correctly.

Wilson considered the Kurumes to be ‘the loveliest of all Azaleas’. Yet they are not widely grown, partly because they are supposed to be tender, partly, perhaps, because they have to compete with more garishly coloured, larger-flowered azaleas bred in Europe and America. A few are definitely tender, but these have mostly dropped out of commerce; the rest are hardier than generally supposed, though like many other ever­green azaleas they may suffer damage from frost when young. The flowers are small, but borne in wonderful profusion in late April or May. In several varieties the calyx is petaloid, i.e., converted into a sort of outer corolla, coloured and marked like the true corolla. Although the result of several generations of breeding, they have retained the dense and comparatively dwarf habit of their wild ancestors. They tolerate full sun, and woodland conditions are quite alien to their nature. Nowhere in Britain can Kurume azaleas be seen in greater number than in Windsor Great Park, where there is an extensive planting in the Valley Gardens and a smaller collection in the Savill Garden.

Modern Hybrids

Until the 1920s, the only evergreen hybrid azaleas suitable for outdoor cultivation in this country had been bred in the gardens of Japan – the only exception being the few hybrids from ‘Amoenum’ such as those raised by William Carmichael. At the present time, the majority of the hybrids commonest in gardens were sent out by Dutch nurserymen. The most valuable of these were raised by P. M. Koster of Koster and Co. by crossing R. kaempferi (seed-parent) with ‘Malvaticum’ (q.v.) The seedlings were sold in 1921 to C. B. van Nes and Sons, who put them into commerce. They take after R. kaempferi in their habit; and also in their foliage, except that the spring leaves mostly have impressed veins, as in the pollen-parent. The flowers of this group range in colour from orange through pink to reddish purple, and are very freely borne in May. Many give brilliant and long-lasting autumn colour. The orange-coloured varieties, such as Anny’ and ‘Alice’, unfortunately share with R. kaempferi the bad quality of fading rapidly in sunny weather – a tendency that can to some extent be mitigated by growing the plants in light shade. The same is true of ‘John Cairns’, another Koster hybrid from R. kaempferi, the other parent of which is uncertain. This was put into commerce by L. J. Endtz and Co.

The so-called Vuyk hybrids were raised by A. Vuyk, founder of the firm Vuyk van Nes. He raised a number of seedlings from various ever­green azaleas pollinated by the Mollis azalea ‘J. C. van Tol’. The offspring show no sign at all of the influence of the latter, and it is now thought that its effect was to induce the seed-parents to set seed apomictically. At any rate, this, rather than self-pollination, is the explanation put forward by H. J. Grootendorst in his work Rhododendrons en Azaleas, to which we are indebted for information concerning the Dutch hybrids. The best known of this set are the lovely ‘Palestrina’, the seed-parent of which was a Malvaticum-Kaempferi hybrid; and ‘Beethoven’ (seed-parent ‘Maxwellii’). For other Vuyk hybrids see ‘Prinz Bernhard’, ‘Vuyk’s Scarlet’, and ‘Vuyk’s Rosy Red’.

Lionel de Rothschild made a few crosses between evergreen azaleas, with his usual success. The best known – ‘Leo’, ‘Eddy’, ‘Naomi’, and ‘Pippa’ – are all hybrids of R. kaempferi and among the best of their class. It is frequently stated that de Rothschild made much use of the Formosan R. oldhamii as a parent, but it is pointed out in The Rothschild Rhododendrons that he used it only once, to produce Bengal Fire (q.v.).

The Glenn Dale Azaleas are the result of a massive hybridisation carried out by B. Y. Morrison at the Plant Introduction Station, Glenn Dale, Maryland, USA, between 1935 and 1940. Altogether 70,000 seedlings were raised from crossings between a wide diversity of species and hybrids, and some 450 clones were eventually selected and named (see further the article by Mr Morrison in R.Y.B. 1951-2, pp. 14-18; and Lee, The Azalea Book (1958), pp. 153-4 and 237-76). These hybrids were selected for use in a region with much warmer summers than ours, but several are succeeding well in Britain, and some have received awards after trial at Wisley. The hybrids raised by J. B. Gable, a nurseryman of Stewartstown, Pennsylvania, are also of diverse parentage. For these see Lee, op. cit., pp. 152-3 and 235-7. Of the Gable hybrids ‘Rosebud’ and ‘Stewartstonian’ are now well established in Britain.

It is not possible to give more than a selection of the evergreen hybrid azaleas cultivated in Britain, but it is hoped that all those mostly widely available in commerce have been included, to which have been added a few that have shown promise in recent trials at Wisley. The evergreen azaleas are certainly a valuable race, especially for labour-saving gardens, as they lend themselves to thicket-planting, But their winter-foliage is far from decorative for the most part, and their colouring is of limited range. In the following descriptions the number of flowers per truss is not given, as it is nearly always small, from one to four.

DESCRIPTIONS

‘Addy Wery’. – Corolla about 112 in. wide and long, of a rather hard shade of bronzy red, with deeper speckling in the upper part. Leaves glossy. Compact habit (Kurume azalea ‘Suetsumu’ × ‘Malvaticum’; H. den Ouden, Holland). A.M.T. May 5, 1950.

‘Anny’. – Corolla orange-red, about 214 in. wide, faintly speckled. Calyx-lobes about 14 in. long, mostly obtuse, sometimes acute (R. kaempferi × ‘Malvaticum’; C.B. van Nes and Son, 1920). ‘Alice’, from the same raiser and of the same parentage, is similar, but the colour is indeterminate, the upper part of the corolla being crimson, shading to orange.

‘Asa-Gasumi’ (‘Rosy Morn’). – Flowers solitary or in pairs. Corolla 114 in. wide, Neyron Rose, scarcely spotted. Calyx petaloid, large, misshapen (Kurume; Wilson No. 14).

‘Atalanta’. – Corolla 214 in. wide, near Mallow Purple, but duller than in ‘Pippa’ (q.v.). Slight coarse, dark speckling on the upper lobe. Style and stamens white. Low growing (R. kaempferi × ‘Malvaticum’; C. B. van Nes). Inferior to ‘Pippa’.

‘Azuma-Kagami’ (‘Pink Pearl’). – Corolla 112 in. wide, pale carmine rose (52d), paling in the throat, with faint speckling. Style and most of stamens malformed, some of the latter slightly petaloid. Calyx large, petaloid, coloured like the corolla. Dense habit (Kurume; Wilson No. 16). There is another azalea in cultivation as ‘Azuma-Kagami’, which is similar to the plant described but has a more deeply lobed corolla, some of the lobes being almost free. It is also of more open, twiggier habit. The plant described is very hardy and free-flowering.

‘Beethoven’. – Corolla 234 in. wide, lilac mauve (78b) with faint speckling, lobes undulated but not frilled (Vuyk van Nes; said to be a hybrid of ‘Max- wellii’). One of the best purples.

‘Bengal Beauty’. – Corolla Neyron Rose with darker speckling, 2 in. wide, margins slightly wavy. Calyx with lobes up to 14 in. long. Early June. Compact habit (R. kaempferi ‘Daimio’ × R. simsii; M. Haworth-Booth). A.M.T. June 3, 1966. Of recent introduction, valuable for its late flowering and holding its colour well. Another clone with flowers in a ‘browner’ shade of pink has been named ‘Final Blush’.

Bengal Fire (kaempferi × oldhamit) – This hybrid, raised at Exbury, shows the influence of the second parent in its conspicuously hairy young leaves and stems. The flowers are about 134 in. wide, and in one clone are dark orange-red, in another lighter and brighter. It is hardy once established and attains about 6 ft.

‘Betty’. – Corolla near Neyron Rose (58c/d) shading to darker along the centre of each lobe, rather narrowly funnel-shaped, about 138 in. wide, with a dark red style and stamen filaments. Calyx-lobes short and broad, obtuse. Upright habit. May. (kaempferi × ‘Malvaticum’; C. B. van Nes). One of the best pinks in this group. It is sometimes grown under the name ‘Kathleen’. What is believed to be the true ‘Kathleen’ has flowers of a similar but more uniform colour, with slight darker speckling near the base of the centre lobe. The style and filaments are pale pink, and the calyx-lobes are large and spreading, up to 14 in. long. It belongs to the same group as ‘Betty’ and is of similar habit.

‘Blaauw’s Pink’. – Flowers hose-in-hose. Corolla 112 in. wide, salmon- pink (38a) but a little darker at the edge and paling at the centre, with slight spotting. Stamens partly petaloid. Calyx almost as long as corolla and of the same colour (J. Blaauw and Co., 1953).

‘Campfire’. – Flowers hose-in-hose. Corolla bright red (53d), slightly speckled, wavy at the margin, 134 in. wide. Calyx almost as large as corolla. Late May. Low, dense habit (Gable, USA). It was sent to the Wisley trials from Holland as “Hino-scarlet” and is described under that name in R.C.Y.B. 1970, p. 195.

‘Chippewa’. – Corolla 212 in. wide, salmon-pink with a redder blotch on the upper lobes. Late June. Low, spreading habit (a hybrid of R. indicum; Bobbink and Atkins, USA).

‘Eddy’. – Corolla 212 in. wide, funnel-shaped from a broad base, with heavy, dark speckling on the upper lobes, margins slightly waved. Stamens nine. Persistent leaves dark green, up to 2 in. long. May. Tall, to about 7 ft (R. kaempferi × Indian azalea ‘Apollo’; Rothschild). A.M. 1944.

‘Favorite’. – Corolla 112 in. wide, vivid crimson-pink, slightly waved at the margin. Bright green, glossy leaves. Early May. Dense habit (R. kaempferi × ‘Hinodegiri’; C. B. van Nes). Very free-flowering.

‘Florida’. – Corolla 212 in. wide, red shaded vermilion with darker speckling on the upper lobes, semi-double owing to the conversion of the stamens into irregularly shaped mostly large extra lobes. Low growing. Late May (Vuyk van Nes). Bud-tender; flowers ugly in form, but of vivid colour.

‘Forsteriana’. – Flowers hose-in-hose. Corolla 118 in. wide, campanulate, near Currant Red (47b). Style and stamens abnormal. Late May or early June. Low and dense (Otto Forster, Lebenhof, Austria, before 1892). A hybrid of ‘Amoenum’, hardy but poorly coloured. Mention may be made here of another of Forster’s hybrids, the once very common ‘Hexe’, which is the result of a cross between ‘Amoenum’ and the Indian azalea ‘Due de Nassau’, raised in 1878. Being of dwarf habit and easily raised from cuttings, it was a very popular pot plant early this century, and was also used as a stock for grafting the Indian azaleas. The flowers are hose-in-hose, rosy crimson, 134 in. wide. A.M. 1907. The name ‘Hexe’ has been wrongly used for a quite different azalea, which is vigorous, late-flowering, and has semi-double flowers with a normal calyx.

‘Frieda’. – Corolla light purple with reddish markings, 112 in. wide; tube slender. Calyx very small, with obtuse lobes. May. To about 5 ft (a hybrid of R. kaempferi; C. B. van Nes, 1952). Very free-flowering.

Gumpo. – The so-called Gumpo azaleas are usually listed under R. simsii var. eriocarpum (Hayata) Wils. (for which see under R. indicum). Whatever may be the status of the wild plants placed under this variety, the Gumpo azaleas, which came from a Japanese nursery, are near to R. indicum and are best treated as a horticultural group of uncertain taxonomic position. All are of low, spreading habit, building up to 2 ft or slightly more in height, and mostly differ from typical R. indicum in their darker, blunter leaves. In common with that species they flower late, in early June. In ‘Gumpo White’ the corolla is pure white, frilled, about 2 in wide; stamens five, with brown anthers. ‘Gumpo Red’, as seen in British gardens, has flesh-pink flowers with darker staining on the upper lobe, not ‘salmon rose’ as stated in the catalogue of Mr Wada, who distributed these Gumpo azaleas from his Hakoneya Nursery before the second world war. It is possible that this pale pink form is the result of propagating a branch-sport of the original ‘Gumpo Red’, since a plant has been seen on which one twig bore flowers agreeing with Wada’s description. The corollas in ‘Gumpo Red’, as seen, are waved and frilled, about 214 in. wide; stamens five, with dark anthers. The true ‘Gumpo Fancy’ has not been seen; it was described by Wada as having pink flowers edged with white. ‘Jitsugesuse’, another member of this group, has Mallow Purple flowers, speckled on the upper lobe. All the Gumpo azaleas are said to be rather tender.

‘Hatsugiri’. – Corolla about 1 in. wide, magenta-purple. Calyx normal. Leaves dark green, oblanceolate. Low, dense habit, 2 to 3 ft high, much more in width. Late April or early May. A Kurume azalea closely related to ‘Amoenum’ but with a normal calyx, differing from most Kurumes in its dull darkish green leaves. Very hardy and free-flowering. F.C.C.T. May 12, 1969.

‘Hinodegiri’ (‘Red Hussar’). – Corolla 1 in. or slightly more wide, with a slender tube, bright red (53b), deepening in the throat. Calyx normal. Leaves light glossy green, the upper (persistent) ones obovate, up to 58 in. long. Late April or early May. Fairly compact habit, eventually 4 or 5 ft high (Kurume; Wilson No. 42). A.M.T. 1965. One of the best known of the Kurumes, not quite hardy. It had been introduced before Wilson sent it.

‘Hinomayo’ (properly ‘Hinamoyo’). – Flowers solitary or in pairs. Corolla 114 in. wide, Phlox Pink, slightly speckled in the throat. Calyx normal. Leaves light glossy green, the upper ones mostly oblanceolate-spatulate. Dense habit, eventually 5 ft high (Kurume). A.M. 1921; Award of Garden Merit 1954. The most popular of the Kurume azaleas and one of the hardiest, already established in gardens before the introduction of the ‘Wilson Fifty’. The flowers are of such a clean shade of pink, and produced in such abundance that the effect of a large group growing in full sun is rather overpowering. It is prettier as an individual specimen or small colony, and flowers quite well in dappled shade. It is one of the most deciduous of the Kurumes, regularly shedding most of its summer leaves, at least in colder gardens, but perfectly bud-hardy. For an interesting note on this azalea by K. Wada, see R.C.Y.B. 1970, pp. 181-3, where it is pointed out that the correct Japanese name is ‘Hinamoyo’.

‘Ima-shojo’ (‘Fascination’). – Corolla 78 in. wide, deep red (Turkey Red); anthers pale, conspicuous. Calyx-segments mostly petaloid, but short and narrow, so the flower is not hose-in-hose. Leaves dark green and glossy, unusually short, even the spring leaves being mostly 34 in. or less long. Very dense habit (Kurume; Wilson No. 36).

‘Irohayama’ (‘Dainty’). – Corolla mauvish pink at the edge, white in the throat, unspeckled or almost so, about 112 in. wide. Style and filaments white. Calyx normal. Dense habit, up to 5 ft (Kurume; Wilson No. 8). A.M. 1952.

‘John Cairns’. – Corolla 134 to 2 in. wide, deep brownish scarlet with darker speckling on the upper lobes. Leaves colouring well in the autumn, the persistent ones deep bronze throughout the winter. Dense habit to about 5 ft high and wide (R. kaempferi hybrid; L. J. Endtz and Co.). Award of Garden Merit 1952.

‘Kimigayo (‘Cherub’). – Corolla tubular-campanulate, 1 to 112 in. wide, Phlox Pink, white in the throat. Dwarf (Kurume; Wilson No. 15). A.M.T. 1952.

‘Kirin’ (‘Daybreak’). – Corolla 114 in. long, with deep, oblong lobes, silvery pink (55b), darker outside. Calyx petaloid, with laciniated lobes, coloured like the outside of the corolla (Kurume; Wilson No. 22, but introduced earlier). One of the prettiest of the Kurumes but not quite hardy. It is sometimes sold by florists in late winter as a pot-plant.

‘Kiritsubo’ (‘Twilight’). – Corolla light rosy mauve, deeper at the edges, about 12 in. wide, with a long tube. Calyx normal in some flowers, in others partly petaloid. Dense habit (Kurume; Wilson No. 24).

‘Koran-yuki’. – Corolla 114 to 112 in. wide, with a short slender tube abruptly widening into the limb, scarlet. Stamens and style long-exserted. Calyx variable, partly petaloid. Dense twiggy habit. Of the Kurume type, introduced from Japan to the Tower Court collection.

‘Kure-no-yuki’ (‘Snowflake’). – Corolla 112 in. wide, white with a faint greenish flare. Calyx petaloid, white, lobes mostly strap-shaped, almost as long as corolla. Compact, dwarf habit (Kurume; Wilson No. 2). Very hardy and free- flowering. A.M.T. 1952.

‘Leo’. – Corolla orange-pink (41b/c), 112 in. wide, with slight purple spotting on the upper lobes. Upper leaves obovate, rounded and mucronate at the apex. Low spreading habit. Late May or early June. A pleasingly coloured hardy, very free-flowering azalea, raised at Exbury.

‘Malvaticum’. – This azalea was found by the Dutch firm of Koster and Co. in a consignment of ‘Hinodegiri’ received from Japan early this century. It had large, mauve flowers with seven to nine stamens, and was probably a hybrid of ‘Hinodegiri’ (or possibly of R. kaempferi), the other parent almost certainly being some form of Mucronatum. It proved to be very hardy, and was used as a parent in breeding the large race of Malvaticum-Kaempferi hybrids (see page 924). It is doubtful whether what is in commerce as ‘Malvaticum’ is really the true clone.

‘Marie’. – Corolla 212 to 234 in. wide, vivid cerise-pink. Calyx petaloid, coloured like the corolla, but some lobes green at the edge. Leaves rather thick. Erect habit, to about 6 ft. May (R. kaempferi × dark red Indian azalea; Roths­child). A very striking but rather tender azalea. ‘Louise’ is of the same parentage and said to be somewhat hardier. It has bright red flowers, and received an Award of Merit in 1939.

‘Martha Hitchcock’. – Corolla 212 to 3 in. wide, slightly frilled, white with a margin of magenta, self-coloured on strong shoots, speckled with reddish brown on the upper lobes. Leaves dull, dark green. Late May or early June. Low spreading habit, to about 4 ft high (Mucronatum × ‘Shinnyo-no-tsuki’; Glenn Dale, USA). A.M.T. June 1, 1972. Lee, The Azalea Book, plates VI and 51. The second parent of this hybrid derives partly from R. indicum, partly from R. simsii (through ‘Elizabeth’, one of the many sports of the famous Indian azalea ‘Vervaeneana’).

‘Maxwellii’. – Corolla funnel-shaped, 234 in. wide, 2 in. long, Rose Bengal (57c) with heavy brown speckling on the upper lobes. Calyx-lobes awl-shaped, spreading, 58 in. long, acute. Leaves rather thin, hairy on both sides, up to 2 in. long. Late May. Low-growing. It is a plant of Japanese gardens, introduced early this century. See further under ‘Phoeniceum’.

‘Mother’s Day’. – Corolla 214 in. wide, with overlapping lobes, crimson (53b), speckled near the bases of the upper lobes. Calyx green with obtuse lobes. Stamens seven, petaloid in some flowers or with petaloid excrescences at the tip. Leaves glossy darkish green, bronze-tinted in winter, broad-elliptic, obtuse, up to 1 in. long or slightly more on strong shoots. Late May. Low spreading habit (Auguste van Hecke, Belgium). F.C.C.T. May 27, 1970.

‘Mrs Carmichael’. – This azalea, which received a First Class Certificate in 1877, was one of the hybrids from ‘Amoenum’ raised by William Carmichael (1815-1904), who was trained in the Edinburgh Botanic Garden under William M’Nab and served as head gardener to the Prince of Wales at Sandringham 1863-73. They were distributed by B. S.Williams of Holloway. ‘Mrs Carmichael’, the other parent of which was the Indian (greenhouse) azalea ‘Stella’, has deep purplish-rose flowers with a darker blotch, and is half-hardy (Millais). It seems to have dropped out of cultivation in this country, but is a parent of some of the American Glenn Dale hybrids.

Mucronatum. – Flowers solitary, in twos or threes; pedicels hairy, sometimes slightly glandular. Corolla widely funnel-shaped, 212 in. wide, white. Stamens eight to ten. Ovary with long, straggly hairs. Calyx-lobes lanceolate, up to about 38 in. long. Spring leaves deciduous, dull green, rather thin, ovate-lanceolate to lanceolate, 1 to 212 in. long, 38 to 34 in. wide, hairy on both surfaces; summer leaves smaller, thicker, persistent. May. A spreading shrub, usually seen under 4 ft high, but attaining 10 ft in the milder parts.

Mucronatum is a plant of Japanese gardens, also cultivated in China, whence it reached Britain in 1819. Under the names Azalea indica alba or A. ledifolia it was cultivated as a pot-plant in the last century but gradually spread into the open garden once it was found to be hardy. When Millais published the first volume of his work on rhododendrons (1917) Mucronatum was still a scarce plant out-of-doors, but was grown in quantity at Leonardslee and South Lodge, as well as in the south-west (where Sir Charles Lemon of Carclew was growing it outside as early as the 1830s). It is quite hardy, stands full sun, and is very pretty at the end of May when covered with its pure white fragrant flowers. In the 1840s and 1850s other white-flowered varieties were raised from it, but there seems to be little doubt that what is grown as ordinary R. mucronatum in this country is the original ‘Indica Alba’ of greenhouses, which later became known as ‘Old White’. See further on p. 921.

The taxonomic status of Mucronatum is a controversial matter. Wilson considered it to be no more than a white-flowered form of R. ripense, and accordingly treated it as a species, under which he placed the wild prototype as a variety – R. mucronatum var. ripense (Makino) Wils. But H. Hara the Japanese authority considers that Mucronatum is part of a garden swarm deriving from R. ripense and R. macrosepalum, and in some degree from R. scabrum and R. kaempferi also (R.Y.B. 1948, pp. 122-4). However, what is grown in this country as R. mucronatum is certainly very near to R. ripense, but apparently some forms cultivated in Japan show the influence of R. macrosepalum quite strongly. The cultivar-name Mucronatum should therefore probably be regarded as indicating a group of horticulturally similar clones, differing slightly from each other in their botanical characters. The botanical synonymy of Mucronatum is: R. mucronatum (Bl.) G. Don; Azalea mucronata Blume; Azalea ledifolia Hook.; R. ledifolium (Hook.) G. Don; Azalea indica var. alba Lindl.; Azalea rosmarinifolia Burmann; R. rosmarinifolium (Burmann) Dipp., not Vidal.

Two named clones in the Mucronatum group are ‘Noordtianum’ and ‘Bulstrode’. The former was introduced to Belgium towards the end of the last century. It has larger flowers and leaves than ordinary Mucronatum and narrow, acute calyx-lobes 34 in. long. For further details, see K. Wada’s note in R.C.Y.B. 1968, pp. 144-5. ‘Bulstrode’ was received by the Sunningdale Nurseries from Bulstrode Park as ‘Oomurasaki’, which clearly it is not (J. Russell, Journ. R.H.S., Vol. 74, p. 148). The flowers are large, beautifully shaped, and have a slight yellow-green eye. For the true ‘Oomurasaki’, see under ‘Phoeniceum’.

Other members of this group are ‘Lilacinum’, with mauve flowers; ‘Fujimanyo’, with rosy-purple double or semi-double flowers (R. mucronatum f. plenum (Sims) Wils.); and ‘Shiromanyo’ (R. mucronatum f. narcissiflorum (Planch.) Wils.), with double white flowers. The two double forms were introduced to cultivation in the last century, and are mentioned by Millais (1917) as being grown out-of-doors in this country, but seem to have dropped out of commerce.

For another member of the Mucronatum group, see ‘Sekidera’.

‘Naomi’. – Corolla 214 in .wide, soft salmon-pink, paler in the centre, slightly speckled with red on the upper lobes. Open habit, to 5 or 6 ft eventually. Late May or early June. A hybrid of R. kaempferi raised at Exbury. It is quite hardy, with flowers of an unusual and attractive colour.

‘Orange Beauty’. – Corolla 112 to 134 in. wide, slightly frilled, soft scarlet (43c), speckled on the upper lobes. Leaves glossy, light green. Low bushy habit, rarely more than 3 ft high but more in width. Late April or early May (R. kaempferi × ‘Hinodegiri’; C. B. van Nes). F.C.C.T. 1958. A well-known and valuable azalea, flowering unfailingly. It is best in slight shade as the flowers fade rather quickly in hot sunny weather.

‘Palestrina’. – Corolla white, about 2 in. wide, with green markings at the base of the three upper lobes. Spring leaves bright green, up to 2 in. long, with impressed veins; persistent leaves darker, up to 1 in. long. An erect shrub, building up to a conical bush about 4 ft high, very free-flowering in May. It was raised in Holland from a Malvaticum-Kaempferi hybrid and shows strongly the influence of Mucronatum, which is one of the parents of ‘Malvaticum’. It is puzzling that there is another clone grown under the name ‘Palestrina’ which has somewhat smaller flowers with less conspicuous markings, shorter leaves and a horizontal habit. There is also a difference in botanical characters. The flowers of the plant described above have seven or eight stamens and a hairy style; in the horizontal, small-leaved plant, which is nearer to R. kaempferi, the stamens number five and the style is glabrous. The latter, at least in a cold garden, is much the finer of the two, being more floriferous, a better grower and with neater, brighter green winter foliage.

‘Phoeniceum’. – This azalea with reddish-purple flowers, now only of historical interest, was introduced to Britain in 1824, and was at one time much used as a stock for grafting the Indian azaleas, also, to some extent, as a parent in their breeding. Its taxonomic status is uncertain, but Wilson considered it to be either a form of R. scabrum, a native of the Ryukyus, or a hybrid between it and R. mucronatum (which he regarded as a good species). The botanical name R. phoeniceum was first published by G. Don in 1834, but two years earlier an azalea raised by William Smith of Norbiton and said to be a hybrid of ‘Phoeniceum’, had been named R. pulchrum by Sweet. Wilson considered this to be not a hybrid but simply a seedling variant of ‘Phoeniceum’, and in consequence the name R. pulchrum Sweet has been used for this ‘species’. But no useful purpose is served, either botanical or horticultural, in subjecting these complex garden productions to orthodox taxonomic treatment. R. scabrum, R. macrosepalum, and R. ripense have been cultivated in Japanese gardens for several centuries and have given rise to a swarm of hybrids and forms of which ‘Phoeniceum’ and similar azaleas are a part. For clones usually placed under R. pulchrum see ‘Maxwellii’ and ‘Tebotan’. Another member of this group is ‘Oomurasaki’, with large, rosy purple flowers heavily spotted on the upper lobes (R. pulchrum var. calycinum (Lindl.) Rehd.). This was introduced by Fortune from China, and again later from Japan, but is apparently not in commerce at the present time.

‘Pippa’. – Corolla Petunia Purple, slightly speckled on the upper lobes, 212 in. wide, with rather narrow lobes. Stamens eight, their filaments coloured like the corolla. Style reddish. Mid-May. Low, spreading, open habit. A beautiful azalea, raised by Lionel de Rothschild, obviously deriving partly from R. kaempferi; as in some other hybrids of this species the tube is translucent, giving a yellow glow to the centre of the flowers and brightening its colour. ‘Pippa’ also shows the influence of Mucronatum, especially in its foliage. R. oldhamii does not enter into its parentage, as erroneously stated in the International Register. It is superior to ‘Atalanta’, which differs in its slightly deeper less pure colouring, white style and filaments, and mostly five stamens; also in its denser habit.

‘Port Knap’. – Corolla 34 to 78 in. wide, with a short tube and spreading limb, Phlox Purple. Early May. Low, spreading habit. Raised at the Knap Hill Nursery. A.M.T. May 13, 1958. It is near to R. kiusianum.

‘Prins Bernhard’. – Corolla 2 in. wide, Geranium Lake, slightly speckled with brown on the upper lobes. Low spreading habit. May (Vuyk van Nes). Others from the same raiser and of similar type are: ‘Prinses Juliana’, with soft orange flowers in late May or early June, low growing; and ‘Koningin Wilhelmina’, vermilion red.

‘Purple Triumph’. – Corolla 214 in. wide, slightly waved at the margin, Cyclamen Purple. Spreading habit. May (Vuyk van Nes).

‘Rashomon’ (‘Meteor’). – Corolla 114 in. wide with a short tube, scarlet. Calyx well developed, with oblong, obtuse lobes. Dense habit, eventually 5 ft high (Kurume; Wilson No. 37).

‘Rosebud’. – Corolla 134 in. wide, Phlox Pink (62b), double, most of the stamens being converted into petals or staminodes. Calyx enlarged, up to 5/8 in. deep, green, or partly or wholly coloured like the corolla. Late May or early June. Spreading habit, ultimate height uncertain (Gable, USA). A charming azalea with truly double flowers, after the style of R. indicum ‘Balsaminiflorum’. A.M.T. 1972. ‘Lorna’, from the same raiser and of the same parentage, is similar. The two parents, both Gable hybrids not commonly available in this country, involve between them five species.

‘Saotome’ (‘Peachblossom’). – Corolla rosy pink (55c), 114 in. wide, tube 12 in. long. Anthers maroon-crimson. Style green (Kurume; Wilson No. 21).

‘Sekidera’. – Corolla 3 in. wide, funnel-shaped, pure white and light purple speckling on the upper lobes. Stamens seven or eight. Calyx-lobes up to 1 in. long, acute; pedicels and edge of calyx-lobes glandular. Low, spreading habit. May. A lovely azalea, not completely hardy. It belongs to the same complex of Japanese garden hybrids as Mucronatum, but is near to R. macrosepalum.

‘Shin-sekai’ (‘Old Ivory’). – Corolla 1 in. wide with a slender tube 12 in. long, and narrow, spreading lobes, creamy white, tube deeper coloured. Style contorted. Calyx irregularly petaloid. Dwarf and compact (Kurume; Wilson No. 3, but introduced earlier). A.M. 1921; A.M.T. 1952. Hardy.

‘Silver Moon’. – Corolla 212 in. wide, white faintly spotted with yellowish green on the upper lobes, slightly waved at the margins. Compact habit, attaining probably 4 ft or so in height. Early June, A.M.T. 1973. A promising azalea of recent introduction, flowering later than the white Mucronatum and ‘Palestrina’. It is one of the many clones raised at Glenn Dale, USA, from a complex cross: (Mucronatum ‘Lilacinum’ × ‘Willy’) × (‘Mrs Carmichael’ × ‘Willy’). Another white of the same parentage, also late-flowering but of lower more spreading habit, is ‘Swansong’, A.M.T. 1972.

Sir William Lawrence. – This name was given by Lionel de Rothschild, apparently as a grex-name, to hybrids raised by him from R. kaempferi crossed with ‘Hinodegiri’ (the cross which, in Holland, produced ‘Orange Beauty’). What is usually offered by nurserymen as ‘Sir William Lawrence’ has flat-faced flowers of a pale shade of Rose Bengal, becoming whiter and translucent at the centre, quite unspotted, 2 in. or slightly more wide, opening in early June. This azalea cannot be of the parentage given for Sir William Lawrence, but presumably came from Exbury originally. It is possibly a hybrid of R. simsii. The plant that received an Award of Merit in 1958 as ‘Sir William Lawrence’ after trial at Wisley has pink flowers with maroon spotting, produced around mid-May.

‘Splendens’. – Corolla 1 to 112 in. wide, funnel-shaped with a narrow tube, deep rosy pink with a redder centre. Calyx normal. Low, spreading habit. Late May or early June. A hybrid between ‘Amoenum’ and some form of R. indicum, free-flowering and quite pretty. Something very like it is in commerce under the incorrect name ‘Caldwellii’. The type ‘Caldwellii’ had hose-in-hose flowers.

‘Stewartstonian’. – Corolla 112 in. wide, deep brownish red (47a), slightly darker in the throat. Stamen-filaments and style red, the latter long-exserted. Leaves glossy, the upper ones obovate to almost rounded, bronze in winter. May. Rather like ‘Addy Wery’. Raised by J. B. Gable, Stewartstown, USA, whence the name, which is often wrongly given as “Stewartsoniana”.

‘Suga-no-ito’ (‘Betty’). – Corolla 112 to 134 in. wide, soft shell-pink, paler in the throat with six pale reddish-brown speckles on the upper lobes. Calyx-lobes elongate and partly petaloid (Kurume; Wilson No. 31). Hardy. According to Lee (The Azalea Book, p. 139), the correct name for this azalea is ‘Kumo-no-ito’.

‘Takasago’ (‘Cherryblossom’). – Corolla 114 in. wide, light shell-pink, slightly deeper at the edge, with pale crimson speckling on the upper lobes. Calyx irregularly petaloid, coloured like the corolla. Not quite hardy (Kurume; Wilson No. 11).

‘Tebotan’. – Corolla double, Mallow Purple, with about eleven segments and a denser cluster of tiny green leaves at the centre. Allied to ‘Phoeniceum’, it has long been cultivated in Japanese gardens, and could be looked on as the counterpart among azaleas of the cherry ‘Fugenzo’. It is said to be rare in Japan, but in 1919 Wilson obtained a plant for the famous Holm Lea collection in Massachusetts (Gard. Chron., Vol. 73 (1923), p. 255). According to him the azalea that used to be sold by Japanese nurserymen as ‘Tebotan’ is really ‘Fujimanyo’ (q.v. under Mucronatum). The true ‘Tebotan’ is cultivated in the Savill Garden and received an Award of Merit when shown by the Crown Estate Commissioners on May 21, 1962. Unfortunately the name ‘Tebotan’ was altered to ‘Violet Cloud’ in Journ. R.H.S., Vol. 87, p. 521, but is perfectly valid as a cultivar-name.

‘Ukamuse’ (‘Princess Delight’). – Corolla 112 in. or slightly more wide, salmon-pink, paler in the throat, with darker speckling on the upper lobes. Calyx irregularly petaloid. Stamen-filaments and style white (Kurume; Wilson No. 47). Hardy.

‘Vida Brown’. – Flowers mostly solitary. Corolla 134 in. wide, crimson, with a large petaloid calyx. Low, spreading habit. Late May or early June. Raised by C. E. Brown and put into commerce by Messrs Stewart, Ferndown, Dorset. A.M.T. 1960.

‘Vuyk’s Rosy Red’. – Corolla 234 to 3 in. across, widely funnel-shaped from a broad base, Neyron Rose, with a brighter red flush in the throat and on the outside, slightly speckled on the upper lobes. Stamens eight or nine, their filaments pink. Style red. Low growing. Late May or early June. (Vuyk van Nes, 1954.) A.M.T. May 31, 1962. Crossed with an unnamed seedling, this has produced ‘Mahler’, with Petunia Purple flowers speckled on the upper lobes, borne in the first half of June.

‘Vuyk’s Scarlet’. – Flowers solitary or in pairs. Corolla funnel-shaped from a broad base, of firm texture, lobes frilled, overlapping, bright crimson (not scarlet), with some darker spotting in the upper part. Low, spreading habit. Early May (Vuyk van Nes, 1954). One of the best and most reliable of the evergreen azaleas. F.C.C.T. May 10, 1966.

‘Willy’. – Corolla 214 in. or slightly more wide, clear rosy pink. Style yellowish white, reddish at the tip. Calyx-lobes relatively broad, obtuse or rounded at the apex, glossy. Leaves mostly deciduous, in some years turning bright red before they fall; the persistent ones bronze in winter. It makes a fairly dwarf flat-topped bush, usually not more than 4 ft high. Mid-May (R. kaempferi × ‘Malvaticum’; C. B. van Nes). Very hardy and free-flowering, the best of its group for cold gardens.

There are several other Malvaticum-Kaempferi hybrids similar to ‘Willy’ in colour, and, for the average garden, just as good, e.g., ‘Fedora’ (F.C.C.T. 1960), ‘Jeanette’ (A.M.T. 1948), ‘Henriette’, and ‘Ivette’. The last-named is easily distinguished by its calyx, some of whose lobes are very long and partly petaloid. But many others of the same colouring were distributed and could no doubt still be found. See also ‘Betty’.

Species articles

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