140 ARISTOCRATS OF THE GARDEN 



years of trial that gardeners learn just what plants can 

 withstand the hot, dry summers and cold, changeable 

 winters characteristic of these parts of eastern North 

 America. The Arnold Arboretum is the only place 

 in this country where data on the comparative hardi- 

 ness of woody plants, covering a long period of years, 

 is to be found. For this reason, this chapter is based 

 on the experiences of that institution. Here and 

 there in gardens, even in the neighborhood of Boston, 

 Mass., a plant thrives which is not hardy in the Arn- 

 old Arboretum. Nevertheless, this Arboretum is the 

 safest guide for all desirous of growing hardy woody 

 plants in the colder parts of the United States of 

 America. Very probably some reader has in his (or 

 her) garden some broad-leaved Evergreen not men- 

 tioned here and this should be a source of joy, for the 

 list in its extreme limits is all too scant. 



We who garden in the cooler parts of eastern North 

 America may envy those of warmer climes their var- 

 iety of broad-leaved Evergreens, yet in the native 

 Mountain Laurel (Kalmia latifolia) we possess one 

 plant that has no superior. The foliage is good 

 at all seasons and in mid- June the broad, dome-like 

 clusters of bowl-shaped flowers, either pure white, or 

 silvery to deepest pink, make a wondrous picture. 

 Truly the Mountain Laurel is in early summer the 



