22 Making a Garden of Perennials 



It is the alternate freezing and thawing 

 that does the most damage, and the surface 

 water lying over the crowns of plants, 

 which the frozen ground underneath does 

 not allow to go down. I have seen roots of 

 shallow-rooted plants, Lobelia cardinalis 

 for instance, growing in clayey soil, lying 

 on the surface of the ground in spring 

 pried out by soil expansion. Part of the 

 covering may be removed quite early but 

 enough should remain to shade the ground. 



