300 



PRINCIPLES AND PRACTICE OF PRUNING 



rapid. It continues until the new growth can elaborate 

 more food than is needed for its maintenance. 



Hence if vines are pruned immediately after the leaves 

 drop the cuttings are in best possible condition for prop- 

 agation. A month later they will not be so good for 

 such purposes, but the largest proportion of food will have 

 been saved in the roots to develop the new spring growth. 

 If pruning is delayed until spring, large quantities of the 

 reser\-e food will be lost in the prunings. Therefore, 

 vines pruned then will develop poorer shoots, but a 

 better set of fruit. 



A'klal also concludes* from three years' experiments that, other 

 conditions being equal, tlie time of pruning modifies only sliglitly 



the numljer of 

 bunches borne. 

 With extremely 

 late pruning the 

 bunches arc more 

 vigorous and the 

 proportion of im- 

 perfect l)unches 

 and aborted flow- 

 ers is less. The 

 individual ber- 

 ries are larger, 

 heavier and more 

 numerous. The 

 growth is more 

 rapid for late 

 pruned vines and 

 continues for a 

 longer time. The 

 \'cgctatiiin is at 

 times diminished 

 and at times in- 

 creased by spring 

 |iruning just as in 

 winter pruning. 

 'Idiese positive or 

 negative variations in vegetation progress or retrogress in more or 

 less regular order with the prugression of the time of pruning. The 

 prunings were made at intcr\'als between J;inuary 1 to about .Ap'dl 

 IT). With \ines pruned .-iftcr tnid-l'~ebruary, the later the pruning 



-X*J' 



^T5i"." 



FIG. 2.^9— VINES HEADED BACK FOR VARIOUS SYS- 

 TEMS OF PRUNING 

 A, The spur and the fan system?; B, the four-arm re- 

 newal system; C, the two-ai'm Kniffin, Munson, um- 

 brella and overhead systems. 



' Compt, Rend. Acad. Sei. No. 17, Pajje 1,102. 



