VIEW THE MOBILE VERSION of Informational Site Network Informational
Home - Origin of Arbor Day   Arbor Day Readings   Arbor Day Celebrations   Arbor Day Programs       Tree Species   Studies of Trees   New England Trees  


RHODODENDRON ARBORESCENS (_syn Azalea arborescens_), from the Carolina

Mountains (1818), is a very showy, late-blooming species. The white,

fragrant flowers, and noble 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 masses of this splendid plant, and

are one of the great sights of the American Continent during the month

of June.

R. CALIFORNICUM.--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 clusters. 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


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. DAHURICUM.--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 sparsely-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. dahuricum 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 clusters 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. ferrugincum,

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. ferrugincum. They are handsome, small-growing, brightly

flowered plants, and worthy of culture.

R. INDICUM.--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.

indicum 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 massing in quantity, 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 clusters. There are several handsome

varieties that vary to a wide extent in the size and colour of flowers.

R. maximum album bears white flowers.

R. MOLLE (_syn Azalea mollis_), from Japan (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

quantity, 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 clusters of white

flowers, margined with rose. It is of dwarf and neat growth, and well

suited for planting on the rock garden.

R. PONTICUM.--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. PONTICUM AZALEOIDES (_syn R. ponticum deciduum_), a hybrid between R.

ponticum 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 clusters. 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 glaucum 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. glaucum, is of remarkably

neat growth, and worthy of cultivation where small-sized kinds are a


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. glaucum, 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


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.

Next: Hardy Hybrid Rhododendrons

Previous: Rhaphithamnus

Add to Add to Reddit Add to Digg Add to Add to Google Add to Twitter Add to Stumble Upon
Add to Informational Site Network

Other R Tree Species