144 LANDSCAPE GARDENING 



one hand by the economic aspects of the problem, 

 and on the other by the esthetic. The height is de- 

 cided upon first because of utilitarian features, and 

 then for harmonization with existing conditions; 

 also to furnish the amount of emphasis or accent 

 required. High shrubs are called background; 

 medium, filler; and low shrubs, facing. In large 

 scale planting the trees may be used as background 

 shrubs. In small scale planting herbaceous plants 

 are often used as facers. 



Plant forms may be roughly divided into rec- 

 tangular, curvilinear, and triangular divisions 

 (Fig. 32), according to the natural shapes of the 

 trees and shrubs. While the groups may embrace 

 numbers of widely different species, some of the 

 commonest varieties are named in the diagram in 

 order to make it easily understood. A more com- 

 plex scheme of classification may seem necessary 

 to some, but the one that is shown has proved very 

 satisfactory for general use. 



The rectangular and curvilinear classes have 

 four subdivisions; the triangular has two. The 

 extremes in each class are used as accent, for the 

 less exaggerated forms are of greatest usefulness, 

 being employed to do the heavy work in most 

 planting plans. These are the filler plants. The 



