280 PRINCIPLES AND PRACTICE OF PRUNING 



(No. 4) is generally done in the winter (Figs. 238, 239). 

 When summer pruning is done, the tips of the young canes 

 are pinched when they reach a height of 18 to 24 inches. 

 An important objection to shortening the red raspberry 

 is that while it develops desirable lateral growth it also 

 encourages the development of undesirable suckers and 

 often unnecessary canes in the stools. The number ac- 

 tually produced will vary more or less with the variety, 

 the character of the soil, the amount of available plant 

 food and other factors. The advantages gained by sum- 

 mer pruning are to increase the bearing wood, and to 

 secure low canes which need no supports. 



FIG. 238 RED RASPBERRY CANES BEFORE PRUNING 

 Note the continuous row as compared with h'lls in Figs. 240, 242. 



Craig* found that with 16 varieties of raspberries the plants 

 whose tips were pinched back twice yielded only about two-thirds 

 as much as vines left unpruned. 



As the result of a five-year test at the Wisconsin Experiment 

 Stationf F. Cranefield writes : The facts lead to the conclusion 

 that pinching the growing shoots of black raspberries, to cause 

 branching, gives rise to a slightly increased production of fruit, 

 while the Cuthbert was decidedly injured by this practice. The 



* Garden and Forest 10, Pages 3-4. 

 t Annual Reports 1899 to 1903 inclusive. 



