68 MANUAL OF AMERICAN GRAPE-GROWING 



little to guide him in selecting stocks and has had to learn by 

 making repeated trials. 



Proper Planting of Grafted Vines 



Europeans and Californians long ago learned that failures 

 with grafted vines often came from setting the vines too deep 

 in the soil, the result being that the cions struck root and 

 became independent, whereupon the stock dies or becomes so 

 moribund that the beneficial effects are lost. There are grape- 

 growers who argue that it is beneficial to the vine to have roots 

 from both stock and cion, but experience and experiments very 

 generally teach the contrary, it being found that in most grafts 

 the cion roots grow more vigorously than stock roots and 

 eventually starve out the latter. The disastrous effects of 

 cion-rooting are often to be found, also, when grafting has been 

 done on old vines in the vineyard ; and, again, when the graft 

 is too close to the root system. 



Another cause of failure is that different stocks require that 

 the vineyard soil be treated differently, especially at planting 

 time. \'ulpina stocks require that the soil be much more 

 deeply plowed than for Viniferas on their own roots, since 

 Vulpinas are deep-rooted and are exacting in the depth of 

 root-run required. Those who have had most experience with 

 resistant stocks maintain that all American grapes require 

 rather deeper plowing than European grapes on their own roots. 



Influence of the Stocks on the Cion 



Up to the present, the growing of grafted grapes has been 

 carried on with little thought of the mutual influence of stock 

 and cion ; grapes have been grafted only to secure vines resistant 

 to phylloxera. Yet there can be no doubt that stock and cion 

 react on one another, and that any variety of grapes is influenced 



