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
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
Other R Tree Species