A thorough knowledge of plant materials and their possible uses in landscape work is of great importance to the landscape-designer, inasmuch as most of the effects he desires to create, in the working out of any problem where plants are employed, depend upon the intelligent use of these plant materials.
In a large way topography affects the design scheme, and this topography may be taken without change, as it occurs in the problem, or it may be altered to suit the requirements better. This alteration will depend upon the extent of the scheme at hand and the amount of money to be laid out upon it.
Planting is often used topographically to give effects of height and to emphasize or obscure elevations. In the diagram showing the section of hillside planting (Fig. 21) it will be seen that the scale of the plant materials has been very carefully arranged to take advantage of the topography.
Plant materials are used in various ways, according to the purpose in view; for the problem of the landscape-designer, aside from determining more or less the general characteristics of the architecture present, is to improve the landscape surroundings of the building, and to tie them and the buildings in with the prevailing type of landscape, wherever his problem may occur. He will use his plant material, then, in many ways: for screening objectionable features, such as service walks and drives and outbuildings (Fig. 22); tying buildings in with their surroundings; calling attention to points of interest that might otherwise have been overlooked, such as a distant view; for the elaborating and harmonizing of architectural detail, as in setting off a monumental building to the best advantage; and in supplying a setting for special features, as for instance, a background for a large scheme or a foreground beyond which the general scheme is to be seen.
Figure 21. HILLSIDE PLANTING TO PRODUCE ILLUSIONS OF GRADE.
As a landscape scheme depends for its chief interest upon the first impression received by the beholder, the importance of the point of view cannot be overemphasized; therefore, as the number of points of view in a problem increases, the complexity of the plant composition increases correspondingly.
The first favorable impression made by a landscape scheme as seen from a distance must be maintained at shorter range, and the massing of plants and shrubs must be accomplished so nicely as to stimulate interest for a nearer view and a closer analysis.
If an estate is beautiful, it need not present a blank wall or screen of plant material to the general public in order to be sufficiently secluded for privacy (Fig. 23); neither is it necessary that its owners, willingly or not, must live in the public eye. It should appear attractive from without, but this attractiveness should be secondary to the more important interest of those who are gazing out from within.
In the planting of large parks or public properties the consideration of varying points of view is found to greater extent perhaps than in any other problems which the landscape-architect may undertake. These are often of small extent, occur generally at the intersection or radiation of streets, and are seen from a number of different points of approach. It is very essential that the park should appear in an equally favorable light from any one of these approaches, and its composition must therefore be much more carefully studied than an off-scape, which is to be seen from one position only.
Planting is often employed in architectural composition to carry out the lines of a design and to unify the general impression. It gives a greater breadth to this impression and emphasizes the salient features. It furnishes an easy transition from one building to another, and is a great help in harmonizing groups of buildings of different types.
A sense of fitness is so evidently lacking in numbers of architects who are called upon to design additions to educational and municipal institutions and groups that it is frequently necessary to employ a great deal of planting in order to make the results bearable. This is particularly true where different architects have been called upon to design buildings of the same group. In such cases there often appears an uncommendable desire to emphasize the particular building under consideration by making it of much more attractive appearance than the other members of the group, rather than a wish to unite diverse elements more closely and add to the collective beauty of the scheme.
Figure 22. THE SORT OF THING THAT DEMANDS SCREENING.
Planting may also create new interests. In many cases where architectural elements are markedly dominant it is impossible to introduce sufficient accent architecturally without either the introduction of a different style or an unwarranted distraction of attention. Many times the needed interest may be supplied by planting without marring the architectural effect. In such cases the lines of the large planting masses are arranged to harmonize with the architectural lines, and accent is obtained by the mass characteristics of the plants. If the problem were of horticultural emphasis, the accent would probably be achieved by varying shapes, sizes, or colors (Fig. 24).
Planting is divided into two classes, according to its use, whether for beauty alone or for more practical purposes. These classes are called the esthetic and the economic.
In the economic class, plant material is employed for strictly utilitarian purposes, beauty being a secondary consideration. It subdivides large schemes, taking the place of more artificial barriers, and screens objectionable features, so that utilitarian buildings, service courts, and other features which are not essentially attractive may be present where they are most needed without marring the general beauty of the scenery. Economic planting is accordingly unobtrusive, and cannot afford to attract direct attention to itself, as in so doing it would disclose the presence of the object which was to have been screened.