PRUNING AND TRAINING THE PLANTS 



547 



greater likelihood of the basal buds being undetermined, or if 

 forced into growth, of being vegetative. 



Although there is practically no experimental evidence rela- 

 tive to the heading back of the laterals of the purple rasp- 

 berries, it has been shown in Missouri that some varieties, 

 such as Cardinal, produce fewer buds along the basal portions 

 of the laterals than black raspberries. With such varieties 

 it seems best to leave the laterals about 18 inches in length. 



At the time of the spring pruning any weak canes should 

 be thinned out. If the canes are vigorous, very little thinning 

 should be practiced as thinning of vigorous canes will greatly 

 reduce yields without materially increasing the size of berries. 

 Likewise, laterals should not be thinned out, unless weak or 

 diseased. 



Usually, after the crop is harvested, the old canes are im- 

 mediately removed and burned. In some regions where heavy 

 snows occur the old canes are sometimes left as a protection to 

 the new ones, but it is generally best to remove and burn them 

 immediately after fruiting in order to destroy any disease 

 which might spread to the new shoots. 



In many regions no trellises are used for black and purple 

 raspberries. By shortening the new shoots in the summer and 

 the resultant laterals in the spring, the plants become stocky 

 and are able to hold up their crops without additional support. 

 In some cases the new canes of each plant are bunched to- 

 gether and tied with a cord just beneath where the laterals 

 emerge, thus helping to keep the plants erect. Occasionally 

 trellises are used and then posts about 30 inches in height at 

 intervals of 25 to 35 feet in the rows are employed. Cross- 

 arms about 18 inches long are fastened to the posts, and No. 12 

 galvanized wire is stretched and fastened to the ends of these 

 arms. This supports the fruiting canes and keeps the fruit 

 out of the mud and dirt. In some regions, no wire is used, but 

 stakes are driven into the ground at each plant and the plants 

 are then tied to these stakes. 



Blackberries. The pruning of the blackberry is quite simi- 



