62 PLANT GROWTH 



that they exhausted the plant but more recently it has been 

 shown that for corn they make as much or more food than 

 they use and that suckering is useless if yield is considered. 



Trimming or shearing is a special type of pruning to make 

 a plant or a group of plants look like a wall or cone. In 

 extreme cases they may be shaped like animals. This trans- 

 fers the attraction from the natural beauty of the plant to 

 that of form. It is difficult to keep such plants in perfect 

 form and otherwise they may be very objectionable. 



Although Dr. L. H. Bailey, the great dean of the plant 

 sciences said, "The time to prune is when the knife is sharp," 

 the better plan is to see that the knife is sharp for the pruning 

 time best suited to each kind of plant. The pinching of 

 buds and small branches can be done at any time, and will, 

 if done carefully, control plant growth so that the removal 

 of large branches is rarely necessary. The removal of larger 

 branches should always be done in the early spring toward 

 the end of the dormant season, when the cut surface dries 

 less and the new growth will soon begin the healing process. 



The time of flowering should govern the pruning of 

 flowering shrubs. If the flower buds are on the old wood, 

 pruning should be delayed until after they flower, otherwise 

 many of the flower-bearing branches are removed, resulting 

 in sparse flowering. This, of course, is desirable in fruit trees 

 and they are pruned in the dormant season. If the flower 

 buds grow on new wood, i.e., spring growth, a rather vigorous 

 dormant pruning will increase the growth of the new shoots 

 and improve the size of the flowers. 



The amount to prune depends on the plant and on the 

 aims of the owner. It has been found by recent experiments 

 that peach and apple trees make larger, quicker-bearing trees 

 if the shaping is done by the removal of buds and small 

 branches instead of the older method of cutting out a large 

 portion of the top each spring. This is probably equally true 

 for other perennials. We usually prune roses heavily be- 



