104 ROCK GARDENING FOR AMATEURS 



was Incarvillea Delavayi, bearing its handsome, some- 

 what trumpet-shaped blooms quite freely. I had never 

 seen it in a wall before. Another wall that haunts the 

 memory still was draped from end to end with white 

 Arabis and mauve Aubrietia ; it was the most exquisitely 

 simple colour scheme I have ever seen. 



The Ideal Wall Garden is built against a bank of soil. 

 It is possible to build a wall having two sides, and filling 

 in between them with soil ; but though the colour display 

 may be equally fine, such a wall lacks the natural charm 

 that distinguishes the other. Readers possessing an old 

 stone wall built against a bank of soil, and smothered 

 perhaps in Ivy or other plebeian creeper, might with little 

 trouble transform it into a paradise of spring and early 

 summer bloom. 



Building and Planting. In building, it is important 

 to ensure that the stones are firmly set as the work pro- 

 ceeds ; when the lowest layer is laid the soil should be 

 well rammed about and behind it. Here and there a 

 stone ought to be placed having one end level with the 

 wall face and the other end deeply embedded in the 

 bank, so that the structure may be strengthened. If these 

 precautions are regarded and care taken to place each 

 layer of stone slightly farther back than the layer below, 

 the wall will be firmly built, and the upper plants will 

 not rob the lower ones of their fair share of moisture. 

 Unless the soil is made quite firm, and all interstices 

 between the stones are carefully filled, it is impossible 

 for the wall to settle properly. 



