170 JOUENAL OF THE KOYAL HORTICULTURAL SOCIETY. 



Layering as applied to these mountain shrubs is not a purely artificial 

 process. They are constantly, at least when they thrive best, being 

 subjected to the same kind of treatment by nature, for in spring the 

 melting snows carry earth and grit and stones down on to them ; and 

 there are some, such as Daphne Blagayana, which soon perish in our 

 gardens unless we imitate this deposit with top-dressing. Top-dressing is, 

 indeed, one of the chief secrets in the culture of alpine plants, and there 

 are some of them, such as most of the Primulas and Aster alpinus 

 which grow out of the soil if they do not get it. No doubt they have this 

 habit because they are used to the natural top dressing of their own 

 mountain snows. They expect an annual deposit and rise up so that they 

 may not be buried under it. But many other plants need this kind of 

 enrichment to encourage them to make new growth in spring, and in the 

 Alps where the snows have just melted you can often see them half buried 

 under the rich gritty soil that has been carried down in the snow. 



I am convinced both from experience in England and from observation 

 in Switzerland, that we do not, as a rule, have rich enough soil in 

 our rock gardens. There are some difficult plants, of course, which 

 will only live in a soil mostly composed of stones and grit ; but these are 

 the exception ; and even these prefer what little soil they want to contain 

 a good deal of humus. But the great mass of alpine plants thrive in 

 a soil as rich as it can be made with decayed vegetable matter. Some are 

 even the better for a deep layer of well decayed manure from a spent hot 

 bed. Those which need but little soil and thrive in a narrow fissure 

 between rocks, yet like that soil to be good and deep, and all alpines like 

 it to be continually enriched with top dressing. Speaking very generally, 

 I may say that the soil of the Alps is usually a thick mass of decayed and 

 decaying vegetable matter, more or less mixed with grit and utterly 

 unlike the hot sandy stuff which many people think good enough for 

 a rock garden. This vegetable enrichment usually goes very deep ; and 

 we need to give alpines in captivity every encouragement to root deeply. 

 Therefore we should give them two or three feet at least of good soil and 

 if this is enriched with yearly top dressings we shall not need to be 

 always shifting our plants about. There are a few that make a rank 

 growth in a rich soil, which rots away in the alternate rains and frosts of 

 our winters, but these are usually rock plants from hotter climates than 

 the Alps, plants like the Onosmas and Aethionemas ; and special 

 provision can be made for them. Most alpines get through the winter 

 best when they have made vigorous growth in the summer, and the 

 best protection against winter rot is not to grow them poorly, but to 

 give them good drainage and a sunny open position free from any kind 

 of drip. You must not suppose that because a plant will thrive under the 

 drip of an overhanging rock in Switzerland it will do the same in England. 

 I have seen Ranunculus glacialis growing fast and strong in the most drippy 

 places ; but we must remember that 9,000 feet up there is no drip in such 

 places in the winter when all moisture is frozen hard. Drip only comes 

 ffith the sudden spring, and then the plants do not mind it. 



But perhaps the most obvious lesson one can learn from alpine 

 flowers growing wild is that they thrive best when they grow close together. 

 I am not speaking of the highest and most difficult plants, such as the 



