The only rules which we can suggest to govern the planter are these: First, if a certain leading expression is desired in a group of trees, together with as great a variety as possible, such species must be chosen as harmonize with each other in certain leading points. And, secondly, in occasionally intermingling trees of opposite characters, discordance may be prevented, and harmonious expression promoted, by interposing other trees of an intermediate character.
In the first case, suppose it is desired to form a group of trees, in which gracefulness must be the leading expression. The willow alone would have the effect; but in groups, willows alone produce sameness: in order therefore, to give variety, we must choose other trees which, while they differ from the willow in some particulars, agree in others. The elm has much larger and darker foliage, while it has also a drooping spray; the weeping birch differs in its leaves, but agrees in the pensile flow of its branches; the common birch has few pendent boughs, but resembles in the airy lightness of its leaves; and the three-thorned acacia, though its branches are horizontal, has delicate foliage of nearly the same hue and floating lightness as the willow.
Here we have a group of five trees, which is, in the whole, full of gracefulness and variety, while there is nothing in the composition inharmonious to the practised eye.
To illustrate the second case, let us suppose a long sweeping outline of maples, birches, and other light, mellow-colored trees, which the improver wishes to vary and break into groups, by spiry-topped, evergreen trees. It is evident, that if these trees were planted in such a manner as to peer abruptly out of the light-colored foliage of the former trees, in dark or almost black masses of tapering verdure, the effect would be by no means so satisfactory and pleasing, as if there were a partial transition from the mellow, pale green of the maples, etc., to the darker hues of the oak, ash, or beech, and finally the sombre tint of the evergreens. Thus much for the coloring; and if, in addition to this, oblong-headed trees or pyramidal trees were also placed near and partly intermingled with the spiry-topped ones, the unity of the whole composition would be still more complete.*
Contrasts, again, are often admissible in woody scenery; and we would not wish to lose many of our most superb trees, because they could not be introduced in particular portions of landscape. Contrasts in trees may be so violent as to be displeasing; as in the example of the groups of the three trees, the willow, poplar, and oak: or they may be such as to produce spirited and pleasing effects. This must be effected by planting the different divisions of trees, first, in small leading groups, and then by effecting a union between the groups of different character, by intermingling those of the nearest similarity into and near the groups: in this way, by easy transitions from the drooping to the round-headed, and from these to the tapering trees, the whole of the foliage and forms harmonize well.
* We are persuaded that very few persons are aware of the beauty, varied and endless, that may be produced by arranging trees with regard to their coloring. It requires the eye and genius of a Claude or a Poussin, to develop all these hidden beauties of harmonious combination. Gilpin rightly says, in speaking of the dark Scotch fir, "with regard to color in general, I think I speak the language of painting, when I assert that the picturesque eye makes little distinction in this matter. It has no attachment to one color in preference to another, but considers the beauty of all coloring as resulting, not from the colors themselves, but almost entirely from their harmony with other colors in their neighborhood. So that as the Scotch fir tree is combined or stationed, it forms a beautiful umbrage or a murky spot." - A. J. D.
"Trees," observes Mr. Whately, in his elegant treatise on this subject, "which differ in but one of these circumstances, of shape, green, or growth, though they agree in every other, are sufficiently distinguished for the purpose of variety; if they differ in two or three, they become contrasts: if in all, they are opposite, and seldom group well together. Those, on the contrary, which are of one character, and are distinguished only as the characteristic mark is strongly or faintly impressed upon them, form a beautiful mass, and unity is preserved without sameness." *
There is another circumstance connected with the color of trees, that will doubtless suggest itself to the improver of taste, the knowledge of which may sometimes be turned to valuable account. We mean the effects produced in the apparent coloring of a landscape by distance, which painters term aerial perspective. Standing at a certain position in a scene, the coloring is deep, rich, and full in the foreground, more tender and mellow in the middle-ground, and softening to a pale tint in the distance.
"Where to the eye three well marked distances Spread their peculiar coloring, vivid green, Warm brown, and black opake the foreground bears Conspicuous: sober olive coldly marks The second distance; thence the third declines In softer blue, or lessening still, is lost In fainted purple. When thy taste is call'd To deck a scene where nature's self presents All these distinct gradations, then rejoice As does the Painter, and like him apply Thy colors; plant thou on each separate part Its proper foliage".
* Observations on Modern Gardening.
Advantage may occasionally be taken of this peculiarity in the gradation of color, in Landscape Gardening, by the creation, as it were, of an artificial distance. In grounds and scenes of limited extent, the apparent size and breadth may be increased, by planting a majority of the trees in the foreground, of dark tints, and the boundary with foliage of a much lighter hue.
An acquaintance, individually, with the different species of trees of indigenous and foreign growth, which may be cultivated with success in this climate, is absolutely essential to the amateur or the professor of Landscape Gardening. The tardiness or rapidity of their growth, the periods at which their leaves and flowers expand, the soils they love best, and their various habits and characters, are all subjects of the highest interest to him. In short, as a love of the country almost commences with a knowledge of its peculiar characteristics, the pure air, the fresh enamelled turf, and the luxuriance and beauty of the whole landscape; so the taste for the embellishment of rural residences must grow out of an admiration for beautiful trees, and the delightful effects they are capable of producing in the hands of persons of taste and lovers of nature.
Admitting this, we think, in the comparatively meagre state of general information on this subject among us, we shall render an acceptable service to the novice, by giving a somewhat detailed description of the character and habits of most of the finest hardy forest and ornamental trees. Among those living in the country, there are many who care little for the beauties of Landscape Gardening, who are yet interested in those trees which are remarkable for the beauty of their forms, their foliage, their blossoms, or their useful purposes. This, we hope, will be a sufficient explanation for the apparently disproportionate number of pages which we shall devote to this part of our subject.