92 PRINCIPLES AND PRACTICE OF PRUNING 



Root pruning is largely practiced by those nurseries which 

 make a specialty of specimen plants several years old. It 

 is performed by passing a large U-shaped knife from end 

 to end of the nursery rows beneath the trees so as to cut 

 the long roots at varying depths. In order to secure best 

 results, the trees are set in check rows, so the second cutting 

 may be done at right angles to the first. This method com- 

 pels the plants to produce many short fibrous roots in a 

 clump close to the base of the stems. The chief advantages 

 of the practice are (1) that the specimens may be traine 1 

 to any desired form in the nursery, where they may remain 

 for several years, all the while becoming more valuable ; 

 and (2) the extensive root system, limited to a small area, 

 is not seriously enough injured in digging to make the cutting 

 of the top necessary to re-establish a balance. 



Root pruning also finds employment in growing dwarf 

 fruit trees and trees trained on walls and in special forms, 

 such as espalier (283) and cordons (282). Unless the 

 work is regularly done the trees are almost sure to de- 

 velop unduly and to frustrate the objects sought. Its 

 practice is mainly limited in America to amateur plantations. 



At Harper-Adams Agricultural College* (England) root and 

 branch pruning experiments during several years stimulated tnv 

 growth considerably, the effect being most marked on the weakest 

 growing variety tested, Cox's Orange Pippin. The most fruit buds 

 were formed on the unpruned trees. 



In an effort to make six espalier pear trees develop fruit buds, 

 R. L. Castlef root-pruned two on both sides, two on one side only. 

 the other two not at all, in January and February. Nothing special 

 was rioted that year, but the following year the trees pruned on one 

 side produced a fair crop of good fruit; those severely pruned bad 

 very few fruits, while those unpruned were still unfruitful. One 

 of the latter trees pruned later gave results similar to the earlier 

 root-pruned trees. 



88. 8. Suckers and water sprouts are produced b\ local 

 or general disturbance of plant equilibrium. The time of 

 year when the pruning is done has less influence upon their 



* Report 1910, Page 52. 

 tjour. Royal Hort. Soc. (London) 29. Nos. 1-3, Pages 146-160. 



