THE PROPAGATION OF APPLE TREES. 



91 



Grafting on Known Roots. 



Once trees are established on roots of known varieties it would seem a 

 desirable process to dig such trees and cut off the greater part of the root 

 system and replant them, that they may re-establish themselves on a 

 renewed root system. Then the roots cut off may be used for grafting 

 in the ordinary manner with scions of the same variety as the root. By 

 this method own-rooted trees should be secured without resorting to the 

 seedling nurse root, the subsequent removal of which is a severe check 

 to the 5'oung tree, especially with those varieties that do not root freely. 



This method was tried out in 1915-16. Trees were dug in the fall and 

 all roots suitable for whip grafting removed and the trees reset, the tops 

 being severely cut back. All recovered and in time became vigorous 

 trees. The roots were stored in moist sand and grafted in February and 

 set in April. For some reason they failed to make a good stand, and 

 those that did grow made less growth than adjoining trees grafted in a 

 similar manner on seedling roots. The number of grafts planted, and the 

 percentages growing in July after planting and also in July a year later, 

 are shown in Table 11. Seedling roots used in grafting are commonly 

 one year old, while some of these roots were three or four years old, 

 and this may have been responsible for the poor stand. The very fine 

 sand in which the roots were stored was rather wet and compact, and 

 this may have interfered with respiration and resulted in injury to the 

 roots. It seems hardly reasonable to suppose that such poor results 

 must necessarily follow grafting on the roots of known varieties. 



Table 11. — Grafts on Knoim Roots. 



