PRUNING— THE SEASON 439 



shoots in the spring may be a valuable means of escaping the injurious effects of 

 spring frosts. In one of our tests, the crop on nine rows pruned Mar. 13, was 

 saved, while that of 12 rows pruned Nov. 19, and Dec. 21, was completely 

 ruined by a frost on Apr. 21. Late pruning also retards the blossoming though 

 somewhat less than it does the starting. Pruning as late as March may retard 

 the blossoming 10 days. The time of ripening is also influenced slightly in the 

 same direction. When spring frosts occur, this influence appears to be reversed. 

 The vines pruned early may blossom and ripen their fruit later. This is because 

 the frost having destroyed the first shoots, the only flowers and fruit which 

 appear are on buds which have started after the frost . . . 



"Pruning may be done, therefore, in frostless locations and with varieties 

 which set their fruit well, at any time when the vines are without leaves. Where 

 spring frosts are common the pruning should be as near the time of the swelling 

 of the buds as possible. The benefits of late pruning without its inconveniences 

 can be obtained by the system of 'double' or (clean) pruning practiced in some 

 regions. This may be applied in various ways. The simplest is to shear off all 

 the canes to a length of 15 to 18 inches at any time during the winter that is 

 convenient. This permits plowing and other cultural operations, and the final 

 pruning is done in April. A better method is to prune the vine as usual but to 

 leave the spurs with four or five e.xtra buds. These spurs we then shortened 

 back to the proper length as late as practicable. In some cases the method 

 practiced in the Medoc may be used. This consists in leaving a foot or 15 inches 

 of cane beyond the last bud needed and removing all the extra buds at the time 

 of pruning. The base buds are said to be retarded by the length of cane above 

 them the presence of buds on the cane having no effect." 



Pruning late in the dormant season is quite likely to be attended by 

 more or less bleeding. Seldom is the amount great enough to be harm- 

 ful though many growers prefer to avoid any. In a few species, 

 as for example, the English walnut, late pruned trees may bleed very 

 profusely and the moist exposed surfaces offer an excellent opportunity 

 for infection. For this reason, if for no other, fall pruning may occa- 

 sionally be preferable to spring pruning. 



Summer Pruning. — In the discussion of the effects attending various 

 amounts of winter pruning there was shown to be a slower net increase in 

 size with pruned than with unpruned trees and the more severe pruning 

 was shown to have the more pronounced retarding influence. Similar 

 results generally follow summer pruning and for about the same reasons. 

 The real question is whether or not summer pruning has a greater retard- 

 ing effect than a correspondingly severe winter pruning of the same kind. 



Influence on Vegetative Growth. — The new shoots and leaves in the 

 spring are built chiefly at the expense of food materials formed the 

 preceding season and stored through the winter. After the leaves are 

 fully expanded they become manufacturing organs and eventually return 

 to the plant a supply of elaborated foods equal to or in excess of that 

 consumed in their development. At first, however, their growth is 



