This section is from the book "Landscape Gardening", by Andrew Jackson Downing. Also available from Amazon: Landscape Gardening.
One of the loveliest charms of a fine park is, undoubtedly, variation or undulation of surface. Everything, accordingly, which tends to preserve and strengthen this pleasing character, should be kept constantly in view. Where, therefore, there are no obvious objections to such a course, the eminences, gentle swells, or hills, should be planted, in preference to the hollows or depressions. By planting the elevated portions of the grounds, their apparent height is increased; but by planting the hollows, all distinction is lessened and broken up. Indeed, where there is but a trifling and scarcely perceptible undulation, the importance of the swells of surface already existing is surprisingly increased, when this course of planting is adopted; and the whole, to the eye, appears finely varied.
Where the grounds of the residence to be planted are level, or nearly so, and it is desirable to confine the view, on any or all sides, to the lawn or park itself, the boundary groups and masses must be so connected together as from the most striking part or parts of the prospect (near the house for example) to answer this end. This should be done, not by planting a continuous, uniformly thick belt of trees round the outside of the whole; but by so arranging the various outer groups and thickets, that when seen from the given points they shall appear connected in one whole. In this way, there will be an agreeable variation in the margin, made by the various bays, recesses, and detached projections, which could not be so well effected if the whole were one uniformly unbroken strip of wood.
But where the house is so elevated as to command a more extensive view than is comprised in the demesne itself, another course should be adopted. The grounds planted must be made to connect themselves with the surrounding scenery, so as not to produce any violent contrast to the eye, when compared with the adjoining country. If then, as is most frequently the case, the lawn or pleasure-ground join, on either side or sides, cultivated farm lands, the proper connection may be kept up by advancing a few groups or even scattered trees into the neighboring fields. In the middle states there are but few cultivated fields, even in ordinary farms, where there is not to be seen, here and there, a handsome cluster of saplings or a few full grown trees; or if not these, at least some tall growing bushes along the fences, all of which, by a little exercise of this leading principle of connection, can, by the planter of taste, be made to appear with few or trifling additions, to divaricate from, and ramble out of the park itself. Where the park joins natural woods, connection is still easier, and where it bounds upon one of our noble rivers, lakes, or other large sheets of water, of course connection is not expected; for sudden contrast and transition is there both natural and beautiful.
In all cases good taste will suggest that the more polished parts of the lawns and grounds should, whatever character is attempted, be those nearest the house. There the most rare and beautiful sorts of trees are displayed, and the entire plantations agree in elegance with the style of art evinced in the mansion itself. When there is much extent, however, as the eye wanders from the neighborhood of the residence, the whole evinces less polish; and gradually, towards the furthest extremities, grows ruder, until it assimilates itself to the wildness of general nature around. This, of course, applies to grounds of large extent, and must not be so much enforced where the lawn embraced is but moderate, and therefore comes more directly under the eye.
It will be remembered that, in the foregoing section, we stated it as one of the leading principles of the art of Landscape Gardening, that in every instance where the grounds of a country residence have a marked natural character, whether of beautiful or picturesque expression, the efforts of the improver will be most successful if he contributes by his art to aid and strengthen that expression. This should ever be borne in mind when we are commencing any improvements in planting that will affect the general expression of the scene, as there are but few country residences in the United States of any importance which have not naturally some distinct landscape character; and the labors of the improver will be productive of much greater satisfaction and more lasting pleasure, when they aim at effects in keeping with the whole scene, than if no regard be paid to this important point. This will be felt almost intuitively by persons who, perhaps, would themselves be incapable of describing the cause of their gratification, but would perceive the contrary at once; as many are unable to analyze the pleasure derived from harmony in music, while they at once perceive the introduction of discordant notes.
We do not intend that this principle should apply so closely, that extensive grounds naturally picturesque shall have nothing of the softening touches of more perfect beauty; or that a demesne characterized by the latter expression should not be occasionally enlivened with a few "smart touches" of the former. This is often necessary, indeed, to prevent tame scenery from degenerating into insipidity, or picturesque into wildness, too great to be appropriate in a country residence. Picturesque trees give new spirit to groups of highly beautiful ones, and the latter sometimes heighten by contrast the value of the former. All of which, however, does not prevent the predominance of the leading features of either style, sufficiently strong to mark it as such; while, occasionally, something of zest or elegance may be borrowed from the opposite character, to suit the wishes or gratify the taste of the proprietor.
 
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