ROCK GARDEN PLANTS 35 



gardens, but only such as are really desirable should 

 be included. The mere fact of rarity should not 

 influence selection : the commonest and easiest grown 

 flowers are often the most beautiful. Nor should too 

 many varieties be grown. It is better to plant two or 

 three representatives of a family in bold groups, than 

 to obtain perhaps four times the number of different 

 species, with but a single plant of each. Hybrids and 

 sub-varieties are often but inferior reproductions of 

 their types, and it is to be regretted that nurserymen 

 should lavish extravagant praise on high priced novelties, 

 ignoring old established favourites because they happen 

 to be both cheap and plentiful. 



However, variety must not be sacrificed to an undue 

 spirit of conservatism. There are certain plants which 

 are perfectly easy to grow, and at the same time give 

 beautiful effects. The temptation to overcrowd the 

 garden with these hardy, free-flowering subjects, which 

 make a lavish display in return for a minimum of trouble, 

 is only too prevalent. In this way less adaptable plants 

 are excluded, and a certain sameness and lack of interest 

 ensues in the rock garden picture. 



For rapidly establishing themselves in cushion-like 

 tufts and mantling the edges of the larger stones, the 

 Rock Cresses (Aubrietia) are unequalled. They will 

 grow in almost any soil, and may be increased by seeds 

 or division. A. purpurea and A. deltoidea are the 

 oldest of the group and have long been favourites in 

 English gardens : A. groeca, lilac-purple, and A. Camp- 

 belli, deep violet-blue, give lighter shades among the 

 purples. Near these, a sheet of snowy Arabis would 

 afford a brilliant contrast, and to complete the picture 

 we would arrange a cluster of golden Alyssum. These 

 three families of rock plants, all perfectly hardy, provide 

 materials for creating one of those bold colour effects, 

 which are often more welcome than subtle harmonies. 



