Quarantine Laboratory), Glenn Dale, Maryland, and the U.S. National 

 Arboretum, Washington, DC. 



Japan has been the primary source of germplasm introduction. It is 

 unfortunate that introductions from other areas of the natural range of 

 /. crenata have been essentially neglected. Wild-origin material from 

 Sakhalin, Kamchatka, Korea, and the People's Republic of China could 

 possibly have increased hardiness and increased resistance to 

 environmental stresses. New germplasm has been recently introduced 

 (1985) from the Republic of Korea and is now being evaluated in the 

 United States and Canada. 



In the 1930's, a successful effort of promotion and distribution by the 

 Arnold Arboretum resulted in the widespread production and sales of 

 /. crenata by the American nursery trade. By the late 1930's a great 

 expansion of single-family suburban dwellings had begun in the United 

 States; concomitantly, affluence and interest in horticulture and 

 landscaping increased, resulting in an equally expanding nursery industry. 

 Foundation plantings and hedges became fashionable, for which /. crenata 

 is eminently suitable. The nursery industry found /. crenata and its many 

 cultivars easy to propagate, and adaptable and useful as landscape plants. 

 Plants may reach saleable size in 2-3 years, and because they grow slowly, 

 they will remain saleable and not become overgrown for 1 -2 years. 

 Transplanting is easy, and the species is tolerant of full sun or shade, 

 exposed sites, and a wide range of soil conditions. It is also highly tolerant 

 of salt and air pollution. As container production became popular in the 

 nursery industry, /. crenata was found to be well adapted to this 

 production technique. It is now thought that /. crenata is the leading 

 broad-leaved evergreen grown by the U.S. nursery industry in both 

 quantities produced and dollar volume. At this time, most plants are 

 container grown. With the national housing boom, market demand 

 continues to be high; and higher prices can be obtained for the evergreen 

 /. crenata than for many deciduous shrubs. 



This species is grown to a limited extent in western Europe and on the 

 west coast of the United States, but it is most adaptable from 

 Massachusetts to the Middle Atlantic and Southeastern States west to 

 Kentucky, Oklahoma, and Texas. The cold hardiness range is generally 

 to 10°F, or USDA zone 7 of the "Plant Hardiness Zone Map" (U.S. 

 Department of Agriculture 1965), but can extend to -20°F, or USDA zones 

 6 and 5, for some cultivars. 



The major cultural problem of/, crenata is its susceptibility to spider 

 mites. Damage from spider mites is more serious in the southern region of 

 its growing range, particularly in the Deep South. Ilex vomitoria, a native 



