288 



THE BOOK OF GARDENING, 



less flat situation, it is best done by cutting a path through the 

 middle of the intended rockery, throwing the soil up on each 

 side so as to form mounds and depressions. When the rough 

 outline has thus been formed, and the bulk of soil placed in 

 position, it must be left for several weeks to solidify before the 

 rockwork is used. The quality of this foundation soil is 

 immaterial so long as it is sufficiently porous to allow of the 

 free passage of water through it ; nevertheless, if this soil is good, 

 so much the better for the plants, as many of them are deep- 

 rooting subjects, and their roots will descend beyond the 

 prepared soil placed in the crevices between the rocks. 



Natural stone is to be preferred when it can be procured, 

 and the kind used will depend upon that found in the neigh- 

 bourhood, as it will be expensive to convey it from a distance. 

 If limestone is obtainable, it should be used, as this gives a very 

 artistic appearance to the rock garden. In some districts it is 

 impossible to obtain natural stone of any description, and when 

 this is the case the use of artificial stone has to be resorted 

 to. This may be made as rough as possible out of brick-rubble 

 and concrete. Carved stones of all kinds should be avoided. 

 The object of the rock is to assist in keeping the roots moist, 

 to help in their healthy development, to prevent undue evapora- 

 tion from the soil, to form the framework of the rockery, and at 

 the same time to provide picturesque growing sites for the 

 plants. 



In making rock gardens, and in disposing of the rocks, it is 

 usual to imitate Nature, but it must be borne in mind that the 

 plants are, or ought to be, the first consideration, and suitable 

 positions must be formed for their reception. The rocks should 

 stand out boldly here and there so as to give variation to the 

 scene, as w^ell as to provide various aspects for the plants. In 

 arranging steep rockwork each piece of stone should slightly 

 recede from the one below it, so that the rain falling on 

 the face of the rocks may find its way into the intervening 

 fissures, and thus supply the roots of the plants with moisture. 

 These fissures must be filled with soil when the rockwork is 

 being built up, so that the plants may have an abundance of 

 soil in which to grow. In arranging ordinary rockwork, pockets 

 and crevices should be left of sufficient size to admit of plenty 

 of soil, and these should be filled with the kind suitable for the 

 particular plants intended to be grown therein. Some alpines, 

 including the rarer ones, delight in narrow crevices, but in all 



