258 Principles of Plant Culture. 



of symmetry may be cut back during the dormant 

 period. 



In pruning for symmetry, the plant should generally 

 be encouraged to develop the form that is natural to 

 the particular species or variety, e. g., the American 

 elm tree,* which naturally develops an open, somewhat 



Fig. 156. Pruning for symmetry. The branches growing beyond 

 the ideal outline, Indicated by the dotted line, should be cut off at 

 the points indicated. 



spreading head, tending to be broadest toward tjie 

 top, should not be pruned to the same form as the 

 sugar maplef that develops a more roundish and com- 

 pact head. Evergreens are sometimes pruned to ideal 

 forms, as in topiary work, a practice that is generally 

 condemned by good taste. 



* Dlmus Americana. 



t Acer saccharinum. 



