80 THE CULTIVATED EVERGREENS 



is easily grown from seed but requires shade for the first two 

 or three years, as is the case with most seedling conifers. 



The most satisfactory spruce for exposed situations is, 

 without doubt, the native white spruce. It is not quite so 

 rapid a grower as the Norway spruce, but makes an annual 

 growth of usually not less than one foot, and its handsome 

 blue-green foliage is much denser than that of the Norway. 

 It is one of the best trees for a windbreak or for dense 

 hedges. This spruce, however, should not be grown in shel- 

 tered positions or anywhere where the summers are extremely 

 dry and hot. 



The Norway spruce is the quickest grower of all the spruces, 

 some trees going upward at the rate of two feet or even more a 

 year. Like the native black spruce, however, the foliage, 

 especially of the lower branches, tends to become ragged and 

 unsightly, and the side of the tree exposed to the severe winds 

 of winter is nearly always less dense than its southern aspect. 

 This is also true of the black spruce which suffers as an orna- 

 mental tree also by reason of its persistent cones, which give 

 the tree a moth-eaten ragged appearance. 



Picea pungens, both in the glauca and green varieties, and 

 P. Engelmanni, are slow growers, seldom making more than 

 six inches of upward growth a year. They appear to have no 

 insect enemies, but P. Engelmanni, the Douglas spruce, and 

 some of the firs frequently lose their leading shoots, apparently 

 from the perverse habit of the birds which perch on the young 

 and tender leaders and sway back and forth in the winds of 

 early spring. However, in the spring of 1923, Douglas spruce 

 was attacked by immense numbers of aphis feeding on the 

 new growth. Several sprayings with fish-oil soap were required 

 to combat this pest. Lime and sulfur were also tried, but 

 had a tendency to burn the needles. 



