Practical hints on planting ornamental trees: with particular reference to coniferae ...
John Standish, Charles Noble
Published by Bradbury and Evans, 1852
No plants of recent introduction have created so much interest as the Sikkim Rhododendrons, discovered and sent to this country by Dr. Hooker during his late botanical mission to the Himalayan Mountains. The exquisite representations of the principal kinds, in " The Rhododendrons of Sikkim Himalaya," have in no small degree contributed to excite and strengthen expectation.
As we possess most of the kinds, and have been very successful in their cultivation, (our plants, we believe, being the largest in the trade,) we have thought that a few hints on their natural history and culture would be very useful to many; especially as they are now in numerous establishments in all parts of the kingdom, and as we are frequently desired to furnish instructions for their cultivation with the plants we send out.
By whatever standard of floral beauty we judge of them they rank very high. Every quality which can possibly render plants attractive is combined in them. Beauty of form, richness and diversity of colour and fragrance, are possessed by them individually or collectively, and in foliage, too, they are equally diversified. Falconeri, a tree thirty feet high, has leaves twelve or eighteen inches long by six inches wide. Argenteum, growing to a similar height, has leaves equal in size, and with large compact globular heads of pure white flowers. Then there is Hodgsoni, with noble foliage and aspect, having large compact ovate heads of pale purple flowers, beautifully and symmetrically arranged. Others widely contrast with these. Setosum, a small and elegant shrub, with flowers resembling a Rhodora, but with evergreen box-like foliage ; and Glaucum, a small shrub, two feet high, with leaves two or three inches long, and loose heads of pale pinkish-purple flowers, will serve as examples. And between these extremes there is great diversity in the character of the several species in height, foliage, and flower. The colours of the latter vary from pure white, or with the faintest tint of rose-colour in Maddeni, Dalhousiae, and Edgeworthii, to the richest and deepest crimson in Thomsoni and fulgens. The latter is especially attractive, from the intensity of colour and polished appearance of its blossoms, which- are in compact globular heads. The flowers of Dalhousiae are remarkable for their thick leathery texture, and for the length of time they remain in perfection, as well as for their delightful fragrance.
For the often-desired combination of yellow flowers with good evergreen foliage in Rhododendrons, Wightii, lanatum, and campylocarpum may be mentioned as examples. Then, in rose-colour, there is Wallichii and glaucum, with an infinite diversity of tint in other species.
The size of these flowers, too, is as remarkable and diversified as their colour. The individual blossoms of Dalhousiae and Edgeworthii are four or five inches across, while those of the very interesting little pumilum and eleagnoides are not more than one inch : and while all are beautiful, each possesses some attractive feature peculiar to itself. Doubts have often been expressed whether the flowers, when produced from plants grown in this country, will equal in size those represented in the published drawing taken from others in their native habitats. We think there is no doubt but that they will exceed rather than fall short of the sizes there shown. The first species— ciliatum—flowered by us, exceeded in the size of its blossoms fully one-third those in the drawing. And there is abundant evidence to show that plants under a good system of cultivation often greatly exceed, both in luxuriance and in the size of their blossoms, others of the same kinds in their native habitats ; and when such are brought from mountainous districts to sheltered situations, these improvements are the more evident.
But independent of their intrinsic beauty, they will offer great resources to the hybridiser, combining as they do so many desirable qualities, necessary for plants occupying exposed situations. These the Sikkim Rhododendrons possess in a remarkable degree. The flower-heads of many of them are very compact and globular, and the texture of the blossoms thick and fleshy— qualities eminently calculated to resist the action of rain and wind. The same may be said of their foliage. The leaves are stout and leathery in texture, with remarkably stout footstalks, rendering them capable of resisting much rough weather. Falconeri, fulgens, and Hodgsoni have these qualities especially conspicuous. From the accounts given by Dr. Hooker of their time of flowering, many of them not putting forth their blossoms till June, we trust they will prove much more valuable as hardy plants than the old arboreum, which, however beautiful it may be, can only be successfully grown out of doors in the more favoured situations in Britain. Whether they will retain their late-blooming qualities in this country must for the present remain an open question; but as the greater part of them are perfectly hardy, if they should be found to bloom earlier than we anticipate from their natural habits, there are many situations in the country where spring frosts are very slightly or not at all felt, in which they may be successfully grown. It is possible, that one or two of the species, as Dalhousiae; and argenteum, may be better suited for the conservatory than the American garden under any circumstances. But whatever situation they may be found best adapted for, any care or attention they may receive will be amply repaid by the great beauty of their flowers.
Not one of their least valuable qualities is the tendency they evince to produce their flowers when in a young state. We had several plants of ciliatum in bloom when but twenty months from the seed, and only three inches high.
As regards their general cultivation, the conditions we have insisted on, in our treatise on "American Plants," will equally apply to them, with this addition, that, if possible, situations having a greater amount of atmospheric moisture should be chosen for them. In bogs drained two or three feet deep they would succeed well. But it must be remembered that, while they will require a moist and cool subsoil, it must not arise from stagnant moisture. In the damp climate of a great part of Ireland, on the southern and western shores of England, and at the base of the mountains on the western coast of Scotland—situations where there is always a large amount of atmospheric humidity, with little frost—these beautiful plants will doubtless succeed well.
To gentlemen already possessing young plants we recommend the following course of treatment:— Procure a quantity of peat soil containing a large amount of vegetable matter, as it is necessary that it should be very rich, to which add about one-fifth silver sand; well mix it, and place a layer of it about six inches deep in the bottom of a frame, in which place the plants at distances according to their size, allowing each plenty of room, and, while growing, shade from the direct influence of the sun, and keep them saturated with moisture. At a corresponding season, on their native mountains, they are deluged with rain : and it is from not affording them sufficient water that many persons have failed in their cultivation. From the want of it, the leaves, especially at the points and edges, become withered and brown.
A great point to be attended to in the cultivation of Rhododendrons, especially when under glass, is never to allow the temperature to get high, nor the atmosphere dry. Nearly all the species are natives of cool and moist regions, and if these (to them) unnatural conditions are allowed to occur, their healthy economy is sure to be materially deranged.
In placing them in the open ground, August will be the best season; a rainy time should, if possible, be chosen, and the plants should not be less than a foot high. After planting, boughs should be stuck in and around them, to afford a partial shade, as well as to prevent evaporation; and of course the plants will have been gradually prepared for their final removal.
From the fact that many of the species were discovered epiphytical on rocks and trees, it has been inferred that corresponding conditions in their culture must be secured in this country. But, from our own experience, we think that little importance in a cultural point of view should be attached to the circumstance, and we are confirmed in our opinion by that of Dr. Hooker, in his very elaborate paper in the volume of " The Journal of the Horticultural Society " for the present year. The localities in which any of the species were found assuming the character of epiphytes were always excessively humid, often in dense woods. And the same species which there occurred as epiphytes became terrestrial in more open, and, of course, drier situations. This character must, therefore, be considered as merely local or accidental, and should by no means influence the course of treatment adopted for them in this country.