162 



THE CENTURY BOOK OF GARDENING. 



a greater difference of levels to appear in the garden, the little alpines being planted on the 

 eminences and the stronger-growing subjects in the lowest positions. Where water is at hand 

 these differences of elevation are particularly valuable, since they admit of a streamlet being 

 brought down by a series of picturesque falls or cascades from the upper to the lower levels. 

 Some rocks of large size should be used and rock masses built, which will provide a nobility of 

 form that must necessarily be absent where stones of a uniform bulk are alone employed. 

 Shelter is valuable where this can be provided without the shade of trees. A screen of shrubs 

 situated at such a distance that their roots will not penetrate the rock garden, and acting as 

 a break to the prevailing winds, is a distinct advantage ; but the rock garden should be open to 

 the fullest sunshine, and shade should be provided for such things as need it by planting them 

 on the sunless side of perpendicular rocks. All large blocks of rock should be placed in position 

 before the soil is added, and the remaining stones introduced as the work proceeds. The soil 

 should be deep, so as to admit of the roots descending or running back between the interstices of 

 the stones, and reaching a depth where the earth remains moist and always of an equable tempera- 



t u r e . If 



shallow 

 it soon 

 cccomes 

 parched 

 i n h o t 

 w e a t h e r , 

 and all but 

 the most 

 vigorous 

 subjects 

 will be 

 liable to 

 perish; 

 but by 

 providing 

 a deep 

 root - run 

 between 

 and at the 

 bases of 



the stones, the plants may enjoy those conditions that the majority of them appreciate so 

 highly, namely, a full exposure to the heat of the sun combined with a moist root-run. 



In the lowest portion of the rock garden a moisture-retaining depression may be formed, 

 where such things as the Lady's Slippers (Cypripedium spectabile, C. acaule, C. Calceolus, 

 C. guttatum, C. japonicum, C. macranthum, and C. pubescens), the Wood Lilies (Trillium 

 grandiflorum and T. sessile californicum), and some of the finer Orchises should flourish, while 

 if a pool of water can be added to the other attractions of the garden, Marliac's beautiful 

 Water-lilies, in their varied colours, may be grown. A few cultural directions as to the 

 requirements of the various plants named in this chapter may prove useful. The Arabis is 

 of the easiest possible culture in any soil not being a clay. A deep root-run is preferable, but 

 even in comparatively shallow soil it grows and flowers well. Acasnas will succeed in ordinary 

 soil and grow well in crevices of rockwork or in the herbaceous border. Achilleas of the Alpine 

 section do best when planted in porous soil on the rock garden, but the stronger-growing species 

 are indifferent as to soil or situation, provided the latter is not sunless. Alyssums grow freely in 

 well-drained garden soil. Androsaces succeed among rock fissures olanted in sandy peat ; 



THE ROCK GARDEN AT HIGHS AM COURT. 



