204 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



We should, in fact, hesitate to use the southern root at all for the 

 northern part of the State, except on decidedly light soil. One should 

 also not attempt to grow it in a nursery where the soil is heavy and wet. 

 In this connection see seedling root rot, or wilt, page 379, a decay of 

 the root of seedlings in very wet or heavy soil. This trouble seems to be 

 limited to this species. The matter of the trees tipping over is not 

 usually a very serious objection, although such trouble does seem more 

 common on this root than on any other. There is some experience 

 available which seems to indicate that for late varieties like Franquette 

 and Eureka, the southern black walnut root is not quite as well adapted 

 as for early varieties like Placectia, Chase, or Prolific. With the latter 



FIG. 25. Ten-year-old Placentia tree on southern California black root. 



it certainiv makes a magnificent tree, as shown in many existing 

 orchards. Even with the late varieties it makes an unusually fine tree, 

 in the nursery at least, and the most uniformly large and the best 

 stands of Eureka which we have ever grown were on this root. 



HYBRID ROOTS. 



The remarkable vigor and rapidity of growth of some walnut trees 

 of hybrid oHgin such as we have described elsewhere has led to the 

 very n?it Mr? I inference that seedlings of such trees should be extremely 

 desirable MS a rootstock for the English walnut. Working on this idea, 

 we have oynerimented with such roots quite largely during the past 

 five years and several other investigators have done the same. 



