THE BOCK GARDEN 97 



interlocked, and depend upon one another, and not upon the soil between 

 them, to keep them in their places. This rule is of the utmost import- 

 ance ; if it is neglected, a long frost or an excessive rainfall may cause 

 the whole structure to collapse. Each successive part of the stone 

 skeleton must be put together before the soil is added. This applies to 

 all rockeries. 



'Size, Aspect, &c. — The most convenient size for the barrow- 

 shaped rockery is about 4 ft. high, and 6 or 7 ft. through at the base. 

 The length is-immaterial. If the long sides face north-east and south- 

 west it will afford perhaps the best variety of aspect ; but the amount 

 of sunshine each plant gets will depend on the arrangement of each 

 stone as much as upon the main structure. 



' There cannot be too many projections, and care must be taken to 

 leave no channels between the stones by which the soil can be washed 

 down to the base. Overhanging brows beneath which plants can be 

 inserted are very useful ; large surfaces of stone may here and there 

 be left exposed, and irregularity of form is far better than symmetry. 

 A formal arrangement of fiat pockets or nests offends the eye with- 

 out helping the cultivator, as the tastes of alpine plants as regards slope 

 of surface and moisture at their roots are very various. 



' As for the degree of slope from base to the summit of the barrow, it 

 will not be uniform. In some places there will be an irregular square 

 yard of level on the top, bounded by large cross key-stones, for which 

 the largest stones should be reserved. In other parts the sides will 

 slope evenly to the ridge ; or the upper half may be perpendicular, 

 leaving only wide crevices to suit the taste of certain plants. 



' If the blocks are very irregular in form, and their points of contact 

 as few as possible, providing only for secure interlocking, there will be 

 plenty of room for soil to nourish the plants. Ever-changing variety 

 of stone surface, both above and below the soil, is the object to be aimed 

 at, and any sort of symmetry must be avoided. 



' The " Facing Rockery."— The second form, or " facing rockery," is 

 dependent upon the natural shape of the ground surface. Wherever 

 there is a steep bank facing south or east, it may be utiHsed for the 

 growth of alpine plants. The stones, as before advised, should be large 

 and unshapely, and be buried to-two thirds of their bulk, and form a 

 very uneven surface, all being interlocked from top to bottom as de- 

 scribed. 



' Eockeries of this form are less liable to suffer from drought ; if the 

 surface covered is large, access to all parts should be provided by con- 

 venient stepping stones, because, although every stone in the structure 

 ought to be capable of bearing the weight of a heavy man without 



