The analogy between gardening and rhetoric is a close one, and it may help to remember that in all language composition unity of subject matter is especially enjoined. If one would write a lecture about the progress of forestry, for example, he must rigorously confine himself to that topic; and no matter how keen he may be to say something on prohibition or child welfare or woman's dress, he must reserve all his ideas on those subjects for another occasion. This is precisely the situation in landscape gardening, only it is not so widely understood, and so we find many persons trying to put everything into one and the same garden plot. Only confusion can result.
Next we may notice that unity of purpose saves many a composition. If we build a school grounds, for example, and every walk, tree, shrub, pump, fence, all contribute clearly and efficiently to school uses, then all these items are thereby unified. On the contrary if there are introduced some things, like a corncrib, a tomb-stone, or a bow-knot flower-bed, not obviously necessary to the purposes of the school, unity is immediately disturbed.
As already mentioned, unity demands clearly that a single style be followed in every work of landscape gardening. The great traditional styles have their own distinguishing characteristics, and one style can not be mixed with another without disastrous results. Even quite minor styles should be kept pure.
Character is also discussed on page 52, where it is explained that in landscape gardening, character refers to the personal qualities contributed to the work by the landscape gardener. Now it is well known that one
man sometimes lays out a park or an estate and that afterwards he is superseded by another park superintendent or another landscape architect. The second man has different ideas and proceeds to alter the plan to suit himself. Perhaps after he has gone his way a third man takes charge and superimposes his plan upon the two already jumbled together upon the grounds. Many examples of this sort are to be found in America and even in Europe, but it is always plain that these compromises of different men's ideas all run to the detriment of the picture. Unity of ideas, that is of character, would be much better.
Design is the very essence of landscape architecture. The landscape architect is ever trying to bring his materials together in some sort of order or design. This means literally that he is trying to build unity out of diversity, probably retaining his diversity at the same time. So he divides his land into areas of sundry sizes and shapes, he builds enclosures, plants borders, lays out walls, and builds up patterns of all kinds. Rut if his design is successful the success lies precisely in building a structure of such strength and obvious unity that all parts of his composition are firmly held together.