322 HORTICULTUKAL MANUAL. 



dormant season, unshapely trees will soon develop fine 

 tops, if headed back as shown in Fig. 88. 



In some cases a single tree of a large-growing species 

 may be made the centre of a tree group by planting rapid- 

 growing species around it, with undergrowth at the 

 boundaries. In other cases where a shade is needed, a 

 single tree may be given room to shade a corner of the 

 grassy lawn. The single spreading white elm or other fine 

 shade tree may also have place in a grassy dell, or hollow 

 of the grounds, where it has ample room to spread in 

 natural form. 



Second-growth timber of varied species is often found 

 on suburban tracts and lots standing too thick for forest 

 or park. On lots some of the trees may be permitted to 

 stand properly thinned and cut back at proper places, but 

 not to interfere with the open lawn or the garden and 

 small fruits in the rear. 



In larger places, where groups are wanted, better effects 

 can often be produced for a few years by permitting the 

 greater part of the thriftiest trees to stand thinning 

 gradually as the tops begin to crowd, or as the primal plan 

 of the grounds require. 



In starting groups the selection of species should be 

 given attention. Evergreens and deciduous trees should 

 not be mixed in the same group, and such trees as cotton-' 

 wood and Lombardy poplar should not be mingled with 

 hard maple and hackberry. The trees and shrub groups 

 should have a harmonious expression. Where not guided 

 by an experienced gardener, the beginner in such work 

 will form tree clumps rather than artistic groups. Many 

 years ago Price wrote: "Natural groups are full of open- 

 ings and hollows, of trees advancing before or retiring 

 behind each other, all productive of intricacy, of variety, 

 of deep shadows, and brilliant lights. In walking about 



