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JOURNAL OF THE EOYAL HORTICULTURAL SOCIETY. 



If rock-work is to be effective it must be massed, not evenly dis- 

 tributed over the whole rock garden; and this can be easily done in 

 a rock garden of varying slopes, for the steeper the slope the closer 

 and larger the rocks should be. Pile your rocks up boldly on your 

 steep, jutting promontories, but on the gradual slopes place a rock here 

 and there with broad spaces between. Above all things, never place 

 a rock without considering what kind of plant is to be grown under it. 

 The rocks are there, first of all, to help the plants to thrive, and not 

 as architecture on their own account. I need scarcely say that all rocks 

 should be placed so that the roots of plants can run under them ; there- 

 fore it is useless to drive them down vertically into the soil; also that 

 they should not overhang the plants so as to make a drip, though there 

 are a few plants that thrive best where an overhanging rock protects 

 them from rain without causing a drip into them. The rocks should be 

 built so that they provide large and small, level, hollowed, and slanting 

 pockets. The proportion of these must depend upon the kinds of plants 

 grown and the climate and natural drainage. A plant like Edraianthus 

 Pu'inilio needs to be wedged into a pocket as small as possible. A plant 

 like Androsace lanuginosa needs a fairly large pocket, so that it may 

 be increased by layers. \ There are many small plants like Campayiula 

 excisa, tho^t like a long narrow pocket, as they run about from place 

 to place, dying out in one spot and throwing up new growth in another. 

 On the other hand, a large-growing plant like Lithospermuin pro- 

 stratu7n can be placed in a small pocket if there is plenty of room below 

 for its roots, as it makes all its growth above ground, and that is the 

 better for resting on rock rather than on the earth. But all this only 

 means that the gardener should know the habits of growth of all his 

 plants and provide for them accordingly. In wet climates, or where 

 the natural drainage is not sharp, most of the pockets for the more 

 difficult alpines should be sloping. In my own dry garden sloping 

 pockets are fatal to plants like Dianthiis alpinus or Androsace carnea that 

 are impatient of drought. They prefer a flat or even hollowed pocket 

 that is very well drained below. Even the easy Androsace lactea dies 

 off in hot weather with me unless planted in a flat place. Speaking 

 generally, those plants need flat pockets, at least in a dry, hot garden, 

 w^hicli do not root very deeply, and so depend upon surface moisture. 

 This cannot be given them in a sloping pocket, as it all runs away. . So 

 for them pockets should be made, which will hold the rain, but drained 

 so that it will run down quickly to their roots and past them. 



As to the artistic arrangement of rocks, the builder must trust his 

 own eye. He can see when the rocks look chaotic or unnatural, as, if 

 he has any experience of rock plants, he can see when they are not 

 fitted for plant life. And he must persevere until they satisfy him. 



1 do not think that general directions are of nuicli use in this matter; 

 so much depends upon the lie of the ground, the character of the rocks, 

 and the plants to be grown. But it is possible to arrange rocks so that 

 they shall seem to be in strata, whether they are continuous or crop 

 out of the grouud here and there; and this can best be done with long 



