176 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



by various parties of the varieties to which he had called attention, and 

 the planting of the best of these, particularly the Franquette, was car- 

 ried on by various people. Without question, the chief credit for the 

 present popularity of the Franquette variety is due to the late Mrs. 

 Emily Vrooman, who planted an extensive grove of this variety near 

 Santa Kosa at a time when walnut growing on a commercial scale in 

 northern California was still considered doubtful or impossible. As 

 a result of the success of Mrs. Vrooman 's grove, others came to appre- 

 ciate the possibilities of walnut culture in the northern part of the 

 State and the valuable qualities of the Franquette variety. In later 

 years there has been a growing interest in walnut culture in the cen- 

 tral and northern part of the State, which has been shared in and 

 assisted by numerous individuals who cannot be mentioned individ- 

 ually here. 



LOCATION FOR WALNUTS. 



CLIMATE. 



The limitations of commercial walnut growing are rather closely 

 drawn by climatic conditions. 



Frost. In regard to temperature, the tree is able to withstand a 

 considerable degree of cold so long as it is not subject to severe frost 

 and freezing outside the period of dormancy, and also provided the 

 trees do not suffer for moisture during the dormant period. English 

 walnut trees are not uncommon in the Atlantic States as far north as 

 New York, and there are trees even in Northwestern New York which 

 bear well every year. The most evident effects of freezing upon the 

 walnut are seen in cases where heavy frosts come on suddenly in the 

 fall while the trees are still green and not yet in a dormant condition, 

 or when the same thing occurs in the spring after the trees have com- 

 menced growth. In the latter case, even in southern California, wal- 

 nut trees are sometimes badly frozen. In general, it may be said that 

 so far as winter temperatures are concerned, the tree is almost as hardy 

 as the peach or apricot and will flourish almost anywhere in California 

 where these trees do well. In regard to late spring frosts, it is for- 

 tunately the case that different walnut trees and varieties vary widely 

 in regard to their time of coming out in the spring, ranging in this 

 respect over a period of several months. It is thus possible in a locality 

 subject to late spring frosts to select a late variety of walnut and thus 

 escape the danger period. It may, therefore, be said in respect to low 

 temperatures that walnuts can be grown in practically all the culti- 

 vated portions of California, so far as this one feature is concerned, by 

 choosing varieties of the proper foliation period in the spring. In the 

 central and northern parts of the State there has been in general too 



