128 Alpine Plants. 
inevitable and indispensable their use often is. On 
the whole it remains then that the chief shelter to 
the small raised rockery is found most practically 
in walling, and any site sheltered by house or 
boundary walls should be turned to account if 
possessing the right aspect and otherwise suitable 
and available. 
In many cases, if the expense is not too great, 
economy of space, suitable position, and efficiency of 
shelter combined can be best and most simply 
secured by building a wall on the north or west, as 
the case may be, at the back of the main bed of the 
rockery and parallel with its principal axis, utilising 
it as a retaining wall against which the final terraces 
of rockwork may be buttressed, the part of the wall 
which remains in sight being always built of similar 
stone to that of which the rockery is itself composed. 
A wall thus incorporated in the rockery can easily 
be masked on its exposed side by a belt of shrubs, 
or by creepers or wall-shrubs grown against it. 
The base of the rock-garden should always lie back 
to the north, and protected from it by a screen. The 
character of this screen and the necessity of additional 
screens depend upon further considerations. 
The vast majority of Alpines flourish upon a 
rockery facing full south, and when the site is 
naturally sheltered, or no winds are troublesome, or 
the east wind is at all bitter or strong, the position 
of the rockery should be such that its long axis runs 
east and west: in this case, a screen or wall on the 
north, together with a little shelter at the east end 
of the rockery if necessary, will prove admirably 
