WILD GARDENS AND ROCK GARDENS 



225 



RY WALL GARDENING 

 Fig. 173. — In dry wall construction the large stones should be placed at the base, and 

 the face of the wall battered back two or three inches to the foot. Pockets of generous 

 dimensions should be provided for the plants, and all the stones should have an inclina- 

 tion toward the bank. In the illustration the plants consist of Armeria, Phlox, Dianthus, 

 Aquilegia and Epimedium. — See page 226 



ing kinds can overrun the weaker, many of which would soon perish 

 under these conditions. 



MOISTURE IMPORTANT 



When a rock garden is constructed on a dry hill it should be 

 provided with a sub-irrigation system, as many Alpine plants require 

 a deep, moist soil. This is very much more important than the 

 shade or partial shade so often thought necessary to their well doing. 

 Such a system of irrigation may be economically installed by running 

 a two-inch agricultural tile along the top of the slope, twelve inches 

 below the surface. The bottom of the trench should be inclined 

 toward the rockery and filled with crushed stone or clean cinders, 

 placed around the tile. The tile should be connected with a rubber 

 hose at the faucet. The use of valves is thus done away with, such 



