Before dealing with the garden and its relation to the house it may be well to say a few words upon Planting. Trees are among the grandest and most ornamental effects of natural scenery; they help the charm of hill, plain, valley, and dale, and the changes in the colour of their foliage at the different seasons of the year give us perpetual delight. One of the most important elements in ornamental gardens is the dividing up and diversifying a given area by plantations, by grouping of trees to form retired glades, open lawns, shaded alleys, and well-selected margins of woods; and, if this be skilfully done, an impression of variety and extent will be produced beyond the belief of the uninitiated who has seen the bare site before it was planted.
To speak generally, there should be no need of apology for applying the most subtle art in the disposal of trees and shrubs, and in the formation of the ground to receive them. "All Art," as Loudon truly says (speaking upon this very point), "to be acknowledged as Art, must be avowed." This is the case in the fine arts—there is no attempt to conceal art in music, poetry, painting, or sculpture, none in architecture, and none in geometrical-gardening.
In modern landscape-gardening, practised as a fine art, many of the more important beauties and effects produced by the artist depend on the use he makes of foreign trees and shrubs; and, personally, one is ready to forgive Brown much of his vile vandalism in old-fashioned gardens for the use he makes of cedars, pines, planes, gleditschias, robinias, deciduous cypress, and all the foreign hardy trees and shrubs that were then to his hand.
Loudon—every inch a fine gardener, true lineal descendant of Bacon in the art of gardening—recommends in his "Arboretum" (pp. 11, 12) the heading down of large trees of common species, and the grafting upon them foreign species of the same genus, as is done in orchard fruit-trees. Hawthorn hedges, for instance, are common everywhere; why not graft some of the rare and beautiful sorts of tree thorns, and intersperse common thorns between them? There are between twenty and thirty beautiful species and varieties of thorn in our nurseries. Every gardener can graft and bud. Or why should not scarlet oak and scarlet acer be grafted on common species of these genera along the margins of woods and plantations?
In planting, the gardener has regard for character of foliage and tints, the nature of the soil, the undulations of ground and grouping, the amount of exposure. Small plantations of trees surrounded by a fence are the best expedients to form groups, says Repton, because trees planted singly seldom grow well. Good trees should not be encumbered by peddling bushes, but be treated as specimens, each having its separate mound. The mounds can be formed out of the hollowed pathways in the curves made between the groups. The dotting of trees over the ground or of specimen shrubs on a lawn is destructive of all breadth of effect. This is not to follow Nature, nor Art, for Art demands that each feature shall have relation to other features, and all to the general effect.
In planting trees the variety of height in their outline must be considered as much as the variety of their outline on plan; the prominent parts made high, the intervening bays kept low,[42] and this both in connection with the lie of the ground and the plant selected. Uniform curves, such as parts of circles or ovals, are not approved; better effects are obtained by forming long bays or recesses with forked tongues breaking forward irregularly, the turf running into the bays. Trees may serve to frame a particular view and frame a picture; and when well led up to the horizon will enhance the imaginative effect of a place: a beyond in any view implies somewhere to explore.
All trees grow more luxuriantly in valleys than on the hills, and on this account the tendency of tree-growth is to neutralise the difference in the rise and fall of the ground and to bring the tops of the trees level. But the perfection of planting is to get an effect approximating as near as may be to the charming undulations of the Forest of Dean and the New Forest. Care will be taken, then, not to plant the fast-growing, or tall-growing trees in the low-ground, but on the higher points, and even to add to the irregularity by clothing the natural peaks with silver fir, whose tall heads will increase the sense of height. The limes, planes, and elms will be mostly kept to the higher ground, bunches of Scotch fir will be placed here and there, and oaks and beeches grouped together, while the lower ground will be occupied by maples, crabs, thorns, alders, &c. "Fringe the edges of your wood with lines of horse-chestnut," says Viscount Lymington in his delightful and valuable article on "Vert and Venery"—"a mass in spring of blossom, and in autumn of colour; and under these chestnuts, and in nooks and corners, thrust in some laburnum, that it may push its showers of gold out to the light and over the fence."
As to the nature of the soil, and degree of exposure suitable to different forest-trees, the writer just quoted holds that, for exposure to the wind inland, the best trees for all soils are the beech, the Austrian pine, and the Scotch fir.
For exposure in hedgerows, the best tree to plant ordinarily is the elm. For exposure to frost, the Insignis pine, which will not, however, stand the frosts of the valley, but prefers high ground. For exposure to smoke, undoubtedly the best tree is the Western plane. The sycamore will stand better than most trees the smoke and chemical works of manufacturing towns. For sea-exposure, the best trees to plant are the goat willow and pineaster. Among the low-growing shrubs which stand sea-exposure well are mentioned the sea-buckthorn, the snow-berry, the evergreen barberry, and the German tamarisk; to which should be added the euonymus and the escallonia.