THE ROCKWORK 71 



damage might be done to the plants growing 

 over and around them. Another advantage 

 also gained by sinking the rocks is that most 

 alpines like to get their roots amongst stones. 



To all rock plants moisture is most essential, 

 but at the same time it must be accompanied 

 by sharp drainage to prevent any water lodging 

 at the roots. For this reason the top surface 

 of all rocks should slope down towards the 

 bank behind, in order that the moisture may 

 be directed towards the roots of the plants 

 growing there. 



The faces of the rocks should not as a rule 

 overhang so as to prevent the rain reaching 

 the ground at their foot, for this would prove 

 fatal to many kinds of plants. There are 

 indeed some, especially those species having 

 woolly leaves, that require some shelter over- 

 head, for damp lying on their leaves soon kills 

 them ; but even these require that their roots 

 be kept moist, which can be achieved by sink- 

 ing flat stones in such a manner as to catch the 

 rain from the rock above and direct it to the 

 roots of the plant. 



In the construction of rockwork, more 



