Pools made in the rock garden, where a series of cascades from pool to pool is constructed, need be nothing more than saucer-shaped depressions in the soil, lined with concrete. The front edge of the concrete should stand forward a little from the rock face, and the lip should be very slightly hollowed out in one place, so that the water overflows as desired into the pool below.
If a real stream is to be constructed artificially, the course must be excavated, and concreted or bricked all along, before any water is introduced.
When it comes to the placing of the main rocks, the garden artist must try to visualize the result of his labours before they happen, and try to create the effect of a natural scene. He should always arrange the rocks so that they appear to be a part of a natural rocky subsoil that has been washed by rain. Natural stone will have this appearance if the weathered parts are exposed.
Another point is that where natural strata are visible in the rocks, the lines of each should be generally parallel, as they would naturally be. True, occasionally through a “ fault “ rocks tilt and overturn, or are pushed out ofby pressure from surrounding rocks; but the general “lie of the land” should be traceable in the rocks. Very round rocks or very thin flat rocks are awkward to place well and should generally be avoided. The flat ones will do for path-making, and a round rock of large size might make an impromptu seat; but in building rock pockets, it will need to be disguised.
Only a part of each rock should generally be visible—roughly about a third—the rest should be buried under the soil. Each rock should rest firmly on another rock, or be so well buried in the soil as to be perfectly secure, even when trodden on. It is quite probable that most of the exposed rocks will, at some time, be used as stepping stones by the gardener, and stones insecurely placed are then a nuisance, if not a danger I think a little might be said here concerning one or two less common styles in rock gardening. All are built on much the same principles as the simpler styles, but there are some rather important differences.
One is the style now known as the alpine meadow. In the mountain valleys, where sun and rain are both plentiful , and where streams and rich fertile valleys are to be found, there are lovely green meadows, starred in springtime withof every hue, and in late summer still coloured with such plants as the , colchicum. These meadows differ entirely from the alpine garden of convention, though affording a home for some similar kinds of alpines; and they are very easy to construct.
The first requisite is a stretch of meadowland, or a sown patch of soil of not too level character, but gently undulating. Over the meadowland are disposed rocks of varying shapes and sizes, carefully set into the turf; so that they appear as a natural outcrop. At one or both sides of the larger rocks a soil patch can be left bare, and the soil displaced by the rocks can be laid there, mixed with good.
Plants of suitable character will then be planted, nestling against , the rocks, in irregular drifts. Ornamental grasses, bulbs, patches of bright rock-carpeting plants, and in some cases dwarf shrubs,, are all materials that the landscape gardener can use in an alpine meadow garden, and they are all equally effective.