52 



The elementary substances absorbed by the roots undergo decompo- 

 sition through the influence of the leaves, and the material is thus pre- 

 pared for further root-growth and extension. The roots have no inherent 

 power of extension, but are dependent upon the health and action of 

 the foliage ; and although in germination the roots are first formed, 

 their growth is due to the action of the foliage of the plant that pro- 

 duced the seed from which they emitted. 



It is, therefore, apparent that the increase in size of the plant, the 

 quality and quantity of its secretions, and the extension of its roots are 

 all dependent upon the healthy action of the leaves. 



When it is considered how essential the foliage is to the healthy de- 

 velopment of the plant, we may well pause before infringing upon the 

 reciprocal action nature has established between the roots and branches, 

 for it is evident that every branch or leaf removed has an effect either 

 for good or for evil upon the plant. The correlative action between 

 the leaves and roots being so intimately connected, it follows that any 

 mdiiuution of leaf growth during the period of active vegetation must 

 retard root development. Hence it is an axiom, now becoming recog- 

 nized, that summer pruning weakens growth, while winter pruning 

 produces a contrary effect. 



Summer pruning can be useful where wood-growth is to be checked, 

 and it will be repressed in proportion to the severity of the removal of the 

 foliage. Fruit trees, when planted in a generous soil, frequently attain 

 a luxuriance incompatible with a fruitful habit, and their flowering may 

 be somewhat hastened by judicious pruning or pinching, so as to retard 

 wood-growth; but care must be exercised, and much observation and 

 experience are requisite before the object can be safely attained. 



Winter pruning invigorates wood-growth. When a portion of the 

 branches of a tree is removed after the fall of the leaves, the balance of 

 growth is destroyed and the roots have the preponderance ; the re- 

 maining buds will now shoot forth with increased vigor an important 

 consideration with trees or vines that have become weakened from over- 

 bearing or any other cause, imparting new vigor to weak and sickly 

 plants. 



The time for winter pruning may be regulated by the condition of the 

 plant; if pruned immediately after the leaves fall or ripen, the shoots 

 will be stronger the succeeding season than they would be if the opera- 

 tion had been delayed until spring. This arises from the fact that dur- 

 ing winter the plant still continues to absorb food by its roots, which 

 is distributed over the branches; and as the principal flow of sap is 

 always directed to the extreme points of shoots, the highest buds are 

 most fully developed. If, therefore, pruning is delayed till spring, this 

 accumulation is cut and thrown away, and to that extent the plant is 

 weakened. Early winter pruning is eminently advantageous to native 

 grapes. As the retained buds become charged with sap during winter, 

 they start and advance rapidly a matter of much moment where the 



