LIMITATIONS OF GRAFTING 229 



(2) Grafting is also used to change the natural habit of 

 growth or stature of a tree. Apples are grafted upon 

 slow-growing sorts that tend to produce a slower growth 

 of the scion. For the same reason, pears are grafted 

 upon quince. Weeping willows and mulberries are often 

 grafted upon stocks producing straight upright trunks, 

 thus forming umbrella-shaped trees. In these as well as 

 in other ways, grafting is used to change the stature of a 

 plant. 



(3) Grafting is used to adapt varieties to soil conditions. 

 Plants are frequently grafted upon stocks that thrive better 

 upon the soil that is to be used to grow them. Plums 

 thrive best upon a moderately heavy soil while peaches 

 prefer a sandy soil. In growing peaches, therefore, upon 

 a heavy soil they are often grafted upon plum stocks, and 

 plums to be grown upon sandy soil may be grafted upon 

 peach stocks. 



(4) Grafting is also used to change an undesirable va- 

 riety to a desirable one. When a tree comes into bearing 

 it may be found to be of an undesirable sort. As it takes 

 ten years for most of our apples to come into bearing, one 

 can hardly afford to destroy a tree and wait for a new one 

 to come into fruit. Upon the branches of the undesirable 

 tree may be grafted the scions of a desirable variety, and 

 in a few years the tree will produce abundant crops of the 

 desired variety. 



Limitations of Grafting. Probably all plants which 

 contain a distinct bark and wood can be grafted. There 

 is no definite rule, however, and the only method of deter- 

 mining the affinity between two kinds of plants is by trial. 

 Under ordinary conditions, however, the following results 

 are obtained. 



