FIFTY BEST ROCK PLANTS 319 



but most vigorous plant, with flowers like those of 

 a delicate little white pink. Both of these should 

 be left undisturbed for some years after they are 

 planted. The Silene does not like a very hot, dry 

 place. For a contrast to C. garganica there is nothing 

 to surpass Asperula hirta, a little woodruff with deli- 

 cate pink flowers, that looks as if it would be difficult, 

 but is almost as easy as Aubretia. But even more 

 beautiful and worthy of the best position in the rock 

 garden is Asperula athoa (or suberosa), a downy little 

 plant with flowers like pink coral, which it bears all 

 through the summer. This is not difficult, but should 

 be planted in a dry fissure between the rocks in full 

 sun and looking south, in a compost consisting mainly 

 of mortar rubble with a little fibrous soil and leaf- 

 mould. It is not a plant for a cold climate, but may 

 be easily grown in the south of England, and can be 

 increased by careful division in spring or by cuttings 

 taken at the same time. It should also be planted 

 in spring. Of all rock plants the Pinks are the most 

 valuable genus, and if one species is to be chosen 

 among them we choose Dianthus neglectus. It is 

 not the easiest, but easier than D. alpinus or the 

 wonderful D. callizonus; and it is perhaps the most 

 beautiful of all. It can be easily raised from seed, 

 but hybridizes too readily with other species. Some 

 seedhngs will probably be inferior, some true, and 

 some may turn out splendid hybrids, finer even than 

 the species. It is a small plant with grassy leaves 

 and brilliant pink flowers washed with yellow on the 



