HOW TO FORM ROCKERIES. 79 



ridge — ^whether, indeed, they are placed on a flat or 

 on a precipitous surface, they should be bedded firmly 

 in. No stone should be left loose and insecure. 



If it be desired to combine a rockery with a pool, a 

 raised " rim " of stones may be set round the edge of 

 the water. If the ground is sloping, the stones may be 

 carried up at the back of the pool. The Alpines, amid 

 the stones, will have a very happy and natural 

 look near the water. Forget-me-nots will luxuriate 

 close to the edge, and long streamers of Rock Cress 

 will dangle towards the pool. 



On a sloping site water for the aquatics can only be 

 retained in summer by artificial means. The soil 

 must be puddled with clay or else sealed with concrete. 

 Puddling is a slow, hard and " messy '' process, and it 

 necessitates a supply of clay, which must be chopped 

 into small pieces and made into a mortar with water. 

 It then requires to be well beaten or trodden to a 

 thickness of at least six inches. On the whole it will 

 be easier, pleasanter and perhaps little more expensive 

 to form a concrete by adding two parts of powdered 

 lime and one of Portland cement to six of gravel or 

 stone chips, and plastering it on to the bottom and 

 sides after making the soil smooth and firm. This 

 sets into a hard crust impermeable by water. If the 

 concrete is carried over to make a wide rim it will form 

 a good base for the first tier of stones. 



Wherever possible the flower-lover should find 

 accommodation for a few hardy aquatics as well as 

 for a collection of Alpines. When the early rock 

 plants are over the water plants will be full of beauty. 



