324 STUDIES IN GARDENING 



teriorate in cultivation. Of the low-growing spring 

 Phloxes there are many varieties, but none so beauti- 

 ful or compact as the white Phlox Nelsoni and the 

 pink P. Vivid. These should be mixed among bold 

 rocks and in a light rich soil. In damp or shady places 

 they are apt to die off in winter. If they are top- 

 dressed with leaf-mould the shoots will root, and this 

 is the best way to increase them. 



There are several Alpine Ranunculi, but none more 

 beautiful or vigorous than R. amplexicauHs, which 

 likes a cool place and a soil of loam and leaf-mould. 

 Of all the Violas, the new Viola gracilis from Greece 

 seems the most valuable for the rock garden. It ap- 

 pears to be hardy and vigorous and has bright but 

 delicate purple flowers. It should be grown in a warm 

 place and light, rich soil, at least until its capacity 

 for standing our winters is better known. Among 

 Veronicas we choose V. prostrata, among PotentUlas, 

 P. alba — both most beautiful plants not so often 

 grown as they should be. P. alba flowers for six months 

 of the year, and will grow almost anywhere. In a 

 large rock garden space should be found for Nierem- 

 bergia rivularis, which in England thrives best in a 

 flat, sunny, well-drained place and should be top- 

 dressed with leaf-mould when it starts into growth 

 in spring. It increases at a great pace, and flowers 

 for a long time. Dryas octopetala also needs a large 

 space, and flowers most freely in full sun when it is 

 protected from drought by large rocks. It likes a 

 strong dose of lime in the soil. There are many good 



