GRAPE PRUNING AND TRAINING 



'663 



to the tendency for all the vigor to go to the ends of the fruit canes. 

 It is difficult to obtain vigorous canes on the renewal spurs. Oc- 

 casional short pruning is usually necessary to keep the vines in 

 proper shape. 



Figure 290 a is similar to c in form, but the number of arms is still 

 further reduced to 2, 3, or at most 4. The unit of pruning is a fruit 

 cane of 2 l /2 to 3 l /2 feet with its renewal spur. Owing to their length* 

 the fruit canes require support and are tied to a high stake. 



This method is used in a large number of Sultanina and Sultana 

 vineyards and for certain wine grapes, especially Semillon and 

 Cabernet. It is not to be recommended in any case, as it has several 

 very serious defects. 



The difficulty of obtaining new wood from the renewal spurs is 

 even greater than in the system shown in Figure 290 c. The length and 

 vertical position of the fruit canes cause the main growth and vigor 

 of the vine to be expended on the highest shoots (73). The renewal 

 spurs are thus so shaded that, even though their buds start, the 

 shoots make but a weak 

 growth. The result is 

 that at the following 

 pruning all the good 

 new wood is at the top 

 of the fruit canes of 

 the previous year, 

 where it cannot be uti- 

 lized. The pruner has 

 to choose then between 

 reverting to spur prun- 

 ing, thus getting no 

 crop, or using the 

 weak growth from the 

 renewal spurs for fruit 

 canes ; In this case he 

 may get blossoms but 

 little or no fruit of any 

 value. 



Other defects of this 

 method are that the 

 fruiting shoots are ex- 

 cessively vigorous and 

 therefore often tend to 

 drop their blossoms 

 without setting and the 

 fruit when produced is 

 massed together so it 

 ripens unevenly and is 

 difficult to gather. It 

 also requires a tall and 

 expensive stake. 



: IG. 282 SULTANINA VINE SHOWING EFFECT 

 OF TYING FRUIT CANES IN VERTICAL 



POSITION 



S, suckers and water sprouts; F, strong fruit 

 wood; /, weak fruit wood; C, previous year's fruit 

 canes which have borne a crop. 



