The author has for some time felt that there was needed in the landscape field, especially by the amateur gardener, a book of this type. He has believed that such a book would be of value to everyone who is interested in the important work of landscape plantings, not only to the amateur but to the expert gardener and to the property owner who has made an exhaustive study of plant uses and plant adaptations.
One of the reasons for the publication of these planting lists for different purposes is that it provides a permanent record for future reference. There is no good reason why a landscape architect thoroughly familiar, as a result of years of experience, study, and observation, with the use of plants should devote his time and thought to the compilation of lists of plants for different purposes, such as wild gardens, spring gardens, rock gardens, and bog gardens in connection with some specific problem only to have each list of material cease to exist for the use of others, as soon as the work in question is completed. Plant lists compiled by capable landscape architects are too frequently used only for one problem, thus requiring the next man who starts to work upon a similar problem to begin his study, not where the other man left off, but at the same point where the other man began, duplicating work and wasting much time and energy. It is not meant to imply that all ornamental plants can be confined within definite standardized lists from which those who attempt to select plants for a specific purpose must choose. It is the author's sincere feeling that lists of plants compiled as the result of the different studies and investigations continually being made, in connection with the landscape problems of many clients, may be accepted as a starting point or a reference beyond which a planter is at full liberty to go when he wishes to use species and varieties which are unusual and rare, or whenever the conditions of his specific problem require it.
The responsibility for the original idea conceived as a basis for the development of this book may be traced to the author's experience in classroom work and in teaching. In this field of work, from a pedav gogical standpoint, he has felt the need of a systematic classification, based upon the association of ideas which would aid in remembering and grouping plants. Through learning to know plants by their group associations a comprehensive knowledge of them may be gathered and retained with little effort. One of the easiest ways of memorizing is through the association of ideas. This is the fundamental principle upon which the information in the various groups is based. The same condition has been found in office work. Men with the greatest range of knowledge covering the identification of plants and the botanical classification of plants have found a smaller book of this kind indispensable as a ready reminder of the possibilities of plant uses, when working out planting designs.
The first abridged edition of this book was published in 1916, primarily for the use of the author and a few of his friends in professional work. It was largely local in character. It has met with such a favourable reception, however, and so many requests have been received asking that a book of this kind be continued, and that the field be covered by comprehensive information, that this revised edition is the result.