Rock Gardens and Alpine Plants 165 



semper vivums, and plants of a more or less succulent character, a soil largely 

 composed of crushed rock or gravel is best. Plants belonging to the primrose 

 and lily families will do best in a soil consisting largely of leaf mould, 

 while for the crucifera?, compositas, and most other families, a good loam 

 is all that is necessary. 



It is a mistake to plant a rock garden too thickly. Each plant should 

 have ample room to develop without encroaching on its neighbour, and 

 those plants which have a tendency to spread unduly, or cannot easily be 

 kept in check, should be rigidly excluded from the rock garden, no matter 

 what other good qualities they may have, for it is difficult to eradicate them 

 from a rock garden when once they are established. 



The matter of exposure requires careful study. The true alpines are 

 better confined to the northern or northeastern aspects, where they would 

 be protected from the midday sun. Plants of a succulent nature, such 

 as the low-growing sedums, may occupy the sunniest positions. The more 

 delicate alpines, such as the alpine primulas or androsaces, should be planted 

 in sheltered nooks. Cerastiums, aubrietras, dwarf phlox, and plants of 

 a similar habit, should be planted to overhang ledges of rock, while the 

 starry saxifrages and sempervivums may occupy holes or crevices in the 

 rocks. For the steepest places, or where it may be difficult for some 

 plants to obtain a foothold, the wild ginger, Asariim Canadense, Arenaria 

 Balearica, or plants of a like habit, are excellent. On the top of the rocks, 

 at the most conspicuous points, or at the turn of the path, may be located 

 such stately plants as Acanthus mollis, Spiraea Aruncus, or a small group 

 of Aqiiilegia Canadensis. A small border, varying in width, and edged with 

 small rough stones, looks well at the foot of the rocky slopes, and not only 

 serves as an edging for the path, but will accommodate many plants, such as 

 the dwarf composites, ajugas, or Iceland poppies. 



Spring-blooming bulbs may be planted in masses among the plants, 

 such as narcissus, scillas, snowdrops, chionodoxas, grape hyacinths, and 

 crocuses. These blossom early and do not interfere with the regular rock- 

 garden plants. Tulips and Dutch hyacinths should never be planted in 

 a rock garden; such highly developed forms are out of place as much as a 

 Japanese chrysanthemum would be in a wild garden. 



The whole rock garden should be enclosed with either flowering shrubs 

 or evergreens planted in masses. These give seclusion and shelter from 

 cold winds, and in their shade native ferns may be planted. 



