Hardy Ornamental Flowering Trees and Shrubs Part 18

RHAMNUS.

RHAMNUS ALATERNUS.--Mediterranean region, 1629. This is an evergreen shrub, with lanceolate shining leaves of a dark glossy-green colour, and pretty flowers produced from March till June. There are several well-marked varieties, one with golden and another with silvery leaves, and named respectively, R. Alaternus foliis aureis, and R. Alaternus foliis argenteus.

R. ALPINUS.--Europe, 1752. This is a neat-growing species, with greenish flowers and black fruit.

R. CATHARTICUS, Common Buckthorn, is a native, th.o.r.n.y species, with ovate and stalked leaves, and small, thickly cl.u.s.tered greenish flowers, succeeded by black berries about the size of peas.

R. FRANGULA.--The Berry-bearing Alder. Europe and Britain. A more erect shrub than the former, and dest.i.tute of spines. The leaves too are larger, and the fruit of a dark purple colour when ripe. More common in Britain than the former.

RHAPHIOLEPIS.

RHAPHIOLEPIS j.a.pONICA INTEGERRIMA (_syn R. ovata_).--A j.a.panese shrub (1865), with deep green, ovate, leathery leaves that are not over abundant, and produced generally at the branch-tips. The pure white, fragrant flowers are plentifully produced when the plant is grown in a cosy corner, or on a sunny wall. Though seldom killed outright, the Raphiolepis becomes badly crippled in severe winters. It is, however, a bold and handsome shrub, and one that may be seen doing well in many gardens around London.

RHAPHITHAMNUS.

RHAPHITHAMNUS CYANOCARPUS (_syn Citharexylum cyanocarpum_). Chili. This bears a great resemblance to some of the th.o.r.n.y Berberis, and is at once a distinct and beautiful shrub. The flowers are large and conspicuous, and of a taking bluish-lilac colour. Having stood unharmed in Ireland through the unusually severe winters of 1879-80, when many more common shrubs were killed outright, it may be relied upon as at least fairly hardy. The soil in which this rare and pretty shrub does best is a brown, fibrous peat, intermingled with sharp sand.

RHODODENDRON.

RHODODENDRON ARBORESCENS (_syn Azalea arborescens_), from the Carolina Mountains (1818), is a very showy, late-blooming species. The white, fragrant flowers, and n.o.ble port, together with its undoubted hardihood, should make this shrub a general favourite with cultivators.

R. CALENDULACEUM (_syn Azalea calendulacea_), from North America (1806), is another of the deciduous species, having oblong, hairy leaves, and large orange-coloured flowers. It is of robust growth, and in favoured situations reaches a height of 6 feet. When in full flower the slopes of the Southern Alleghany Mountains are rendered highly attractive by reason of the great flame-coloured ma.s.ses of this splendid plant, and are one of the great sights of the American Continent during the month of June.

R. CALIFORNIc.u.m.--California. A good hardy species with broadly campanulate rosy-purple flowers, spotted with yellow.

R. CAMPANULATUM (_syn R. aeruginosum_).--Sikkim, 1825. A small-growing species, rarely over 6 feet high, with elliptic leaves that are fawn-coloured on the under sides. The campanulate flowers are large and showy, rose or white and purple spotted, at the base of the three upper lobes. In this country it is fairly hardy, but suffers in very severe weather, unless planted in a sheltered site.

R. CAMPYLOCARPUM.--Sikkim, 1851. This has stood the winter uninjured in so many districts that it may at least be recommended for planting in favoured situations and by the seaside. It is a Sikkim species that was introduced about forty years ago, and is still rather rare. The leaves are about 4 inches long, 2 inches wide, and distinctly undulated on the margins. Flowers bell-shaped, about 2 inches in diameter, and arranged in rather straggling terminal heads. They are sulphur-yellow, without markings, a tint distinct from any other known Indian species.

R. CATAWBIENSE.--Mountains from Virginia to Georgia, 1809. A bushy, free growing species, with broadly oval leaves, and large campanulate flowers, produced in compact, rounded cl.u.s.ters. They vary a good deal in colour, but lilac-purple is the typical shade. This is a very valuable species, and one that has given rise to a large number of beautiful varieties.

R. CHRYSANTHUM is a Siberian species (1796) of very dwarf, compact growth, with linear-lanceolate leaves that are ferruginous on the under side, and beautiful golden-yellow flowers an inch in diameter. It is a desirable but scarce species.

R. COLLETTIANUM is an Afghanistan species, and one that may be reckoned upon as being perfectly hardy. It is of very dwarf habit, and bears an abundance of small white and faintly fragrant flowers. For planting on rockwork it is a valuable species.

R. DAHURIc.u.m.--Dahuria, 1780. A small-growing, scraggy-looking species of about a yard high, with oval-oblong leaves that are rusty-tomentose on the under sides. The flowers, which are produced in February, are purple or violet, in twos or threes, and usually appear before the leaves. It is a spa.r.s.ely-leaved species, and of greatest value on account of the flowers being produced so early in the season. One of the hardiest species in cultivation. R. dahuric.u.m atro-virens is a beautiful and worthy variety because nearly evergreen.

R. FERRUGINEUM.--Alpine Rose. Europe, 1752. This dwarf species, rarely exceeding a yard in height, occurs in abundance on the Swiss Alps, and generally where few other plants are to be found. It is a neat little compact shrub, with oblong-lanceolate leaves that are rusty-scaly on the under sides, and has terminal cl.u.s.ters of rosy-red flowers.

R. FLAVUM (_syn Azalea pontica_).--Pontic Azalea. A native of Asia Minor (1793), is probably the commonest of the recognised species, and may frequently, in this country, be seen forming good round bushes of 6 feet in height, with hairy lanceolate leaves, and large yellow flowers, though in this latter it varies considerably, orange, and orange tinged with red, being colours often present. It is of free growth in any good light peaty or sandy soil.

R. HIRSUTUM.--Alpine Rose. South Europe, 1656. Very near R. ferruginc.u.m, but having ciliated leaves, with glands on both sides. R. hallense and R. hirsutiforme are intermediate forms of a natural cross between R.

hirsutum and R. ferruginc.u.m. They are handsome, small-growing, brightly flowered plants, and worthy of culture.

R. INDIc.u.m.--Indian Azalea. A native of China (1808), and perfectly hardy in the more favoured portions of southern England, where it looks healthy and happy out of doors, and blooms freely from year to year.

This is the evergreen so-called Azalea that is so commonly cultivated in greenhouses, with long hirsute leaves, and large showy flowers. R.

indic.u.m amoenum (_syn Azalea amoena_), as a greenhouse plant is common enough, but except in the South of England and Ireland it is not sufficiently hardy to withstand severe frost. The flowers are, moreover, not very showy, at least when compared with some of the newer forms, being dull magenta, and rather lax of habit.

R. LEDIFOLIUM (_syns Azalea ledifolia_ and _A. liliiflora_).--Ledum-leaved Azalea. China, 1819. A perfectly hardy species. The flowers are large and white, but somewhat flaunting. It is, however, a desirable species for ma.s.sing in quant.i.ty, beside clumps of the pink and yellow flowered kinds. Though introduced nearly three-quarters of a century ago, this is by no means a common plant in our gardens.

R. MAXIMUM.--American Great Laurel. North America, 1756. This is a very hardy American species, growing in favoured localities from 10 feet to 15 feet high. Leaves oblong-lanceolate, slightly ferruginous beneath.

Flowers rose and white, in dense cl.u.s.ters. There are several handsome varieties that vary to a wide extent in the size and colour of flowers.

R. maximum alb.u.m bears white flowers.

R. MOLLE (_syn Azalea mollis_), from j.a.pan (1867), is a dwarf, deciduous species of neat growth, with flame-coloured flowers. It is very hardy, and a desirable acquisition to any collection of small-growing shrubs.

R. OCCIDENTALE (_syn Azalea occidentalis_), Western Azalea, is valuable in that the flowers are produced later than those of almost any other species. These are white, blotched with yellow at the base of the upper petals; and being produced when the leaves are almost fully developed, have a very pleasing effect, particularly as they are borne in great quant.i.ty, and show well above the foliage. This is a Californian species that has been found further west of the Rocky Mountains than any other member of Ihe family.

R. PARVIFOLIUM.--Baiacul, 1877. This is a pleasing and interesting species, with small deep-green ovate leaves, and cl.u.s.ters of white flowers, margined with rose. It is of dwarf and neat growth, and well suited for planting on the rock garden.

R. PONTIc.u.m.--Pontic Rhododendron, or Rose Bay. Asia Minor, 1763. This is the commonest species in cultivation, and although originally a native of the district by the Black or Pontic Sea, is now naturalised in many parts of Europe. It is the hardiest and least exacting of the large flowered species, and is generally employed as a stock on which to graft the less hardy kinds. Flowers, in the typical species, pale purplish-violet and spotted. There is a great number of varieties, including white, pink, scarlet, and double-flowering.

R. PONTIc.u.m AZALEOIDES (_syn R. pontic.u.m deciduum_), a hybrid between R.

pontic.u.m and a hardy Azalea, is a sub-evergreen form, with a compact habit of growth, and bearing loose heads of fragrant lavender-and-white flowers. It is quite hardy at Kew.

R. RACEMOSUM.--Central China, 1880. A neat little species, of dwarf, compact growth, from the Yunnan district of China. The flowers are pale pink edged with a deeper tint, about an inch across, and borne in terminal and axillary cl.u.s.ters. It has stood unharmed for several years in southern England, so may be regarded as at least fairly hardy. Its neat dwarf growth, and flowering as it does when hardly a foot high, renders it a choice subject for the Alpine garden.

R. RHODORA (_syn Rhodora canadensis_).--North America, 1767. In general aspect this shrub resembles an Azalea, but it comes into flower long even before R. molle. Being deciduous, and producing its pretty purplish sweet-scented flowers in early spring, gives to the plant a particular value for gardening purposes, clumps of the shrub being most effective at the very time when flowers are at their scarcest. It thrives well in any peaty soil, and is quite hardy.

R. VISCOSUM (_syn Azalea viscosa_).--Clammy Azalea, or Swamp Honeysuckle. North America, 1734. This is one of the hardiest, most floriferous, and easily managed of the family. The white or rose and deliciously fragrant flowers are produced in great abundance, and impart when at their best quite a charm to the shrub. It delights in rather moist, peaty soil, and grows all the stronger and flowers all the more freely when surrounded by rising ground or tall trees at considerable distance away. The variety R. viscosum glauc.u.m has leaves paler than those of the species; and R. viscosum nitidum, of dwarf, compact growth, has leaves deep green on both sides.

R. WILSONI, a cross between R. ciliatum and R. glauc.u.m, is of remarkably neat growth, and worthy of cultivation where small-sized kinds are a desideratum.

The following Himalayan species have been found to thrive well in the warmer parts of England, and in close proximity to the sea;--R.

argenteum, R. arboreum, R. Aucklandii, R. barbatum, R. ciliatum, R.

campanulatum, R. cinnabarinum, R. Campbelli, R. compylocarpum, R.

eximium, R. Fortunei, R. Falconeri, R. glauc.u.m, R. Hodgsoni, R. lanatum, R. niveum, R. Roylei, R. Thompsoni, and R. Wallichii.

R. Ungernii and R. Smirnowii, from the Armenian frontier, are also worthy of culture, but they are at present rare in cultivation in this country.

Few hardy shrubs, it must be admitted, are more beautiful than these Rhododendrons, none flowering more freely or lasting longer in bloom.

Their requirements are by no means hard to meet, light, peaty soil, or even good sandy loam, with a small admixture of decayed vegetable matter, suiting them well. Lime in any form must, however, be kept away both from Azaleas and Rhododendrons. They like a quiet, still place, where a fair amount of moisture is present in the air and soil.

HARDY HYBRID RHODODENDRONS.

GHENT AZALEAS, as generally known, from having been raised in Belgium, are a race of hybrids that have been produced by crossing the Asiatic R.

pontica with the various American species noted above, but particularly R. calendulaceum, R. nudiflorum, and R. viscosum, and these latter with one another. These have produced hybrids of almost indescribable beauty, the flowers of which range in colour from crimson and pink, through orange and yellow, to almost white.

Within the last few years quite an interesting race of Rhododendrons has been brought out, with double or hose-in-hose flowers, and very appropriately termed the Narcissiflora group. They include fully a dozen highly ornamental kinds, with flowers of varying shades of colour.

The following list includes some of the best and most beautiful of these varieties:--

Alba marginata.

Ardens.

Astreans.