56 STUDIES IN GARDENING 



for instance, are always likely to suffer from drought, 

 and also plants whose roots are very fine and delicate. 

 The roots of some of the more delicate Alpines are 

 like silk, whereas the roots of plants like the Aethione- 

 mas, which will endure any amount of drought, are 

 thick and strong. Further, it is easy to see that a 

 plant which grows like a tree from a single trunk or 

 crown will need a much smaller surface of soil in which 

 to grow to its full size than a plant which spreads in 

 a mossy tuft or by means of runners under the soil. 

 Some of the plants which increase by means of runners 

 need only a very narrow crevice or pocket between 

 the rocks in which to spread, but it must be long as 

 well as narrow. Such a plant, for instance, as Cam- 

 panula pulla will thrive in a long slit full of leaf -mould 

 and rubble, but if confined by rocks on all sides it 

 will soon die out. All Alpine plants must be kept 

 quite free from drip, and, therefore, no rocks must 

 overhang them. The plants of the higher Swiss Alps 

 usually prefer a south-west or a south-east aspect, 

 those which suffer from drought or which flower very 

 early doing best when they look towards the south- 

 west. The Alpines from hot climates, such as the 

 Aethionemas, the Wahlenbergias (except W. hedera- 

 cea, which needs moisture and half shade), and the 

 Onosmas should be placed on a slope looking full 

 south. All Alpines when planted should be pressed 

 very tightly into the ground. There is no detail in 

 their culture more important than this; and after a 

 sharp frost they should be examined to see whether 



