Once you choose the site of your rock garden, select the rocks you want to use and have the soil prepared, you are ready to start construction. The first question you might as is when is the best time of year to make a rock garden? The rocks and soil may be handled at any time except when the ground is frozen, but the summer months offer the longest period of freedom from planting rush, and then the soil is dry and easily handled.

Then there will be autumn rains to make the soil firm and winter frost to settle the rocks and planting can best be done the following spring. The first thing you need to do is to dig off the existing topsoil (the first foot of earth) and remove the roots of all weeds and grasses. Much of this soil may be used in backfilling if all roots are sifted out. On this base the large bulky rocks should be laid, each packed around with soil, well rammed, and topped by several chinker stones, large water features, outdoor fountains, or garden statuary before the next are put into place.

As the program for procedure has already been arranged, the work of laying up the rocks can proceed. Now is the time to worry over the details of the outline of the structure. You may have decided the general shape of the area in advance and may even have a plan at hand to give the principal elevations and major masses. However, you must decide the details of the shape of each crag and ravine as the rock garden is being constructed.

The aim is to give the greatest variety in configuration in a small compass, with an appearance of geologic truth and yet make the best possible home for each plant. For the best growth of many rock plants it is well to separate the groups by little walls of stones, outdoor water features, garden statuary, or large fountains, making a pocket for each. Not only are they thus separated, but the plant roots will follow down the cool rock faces and withstand the rigors of summer and winter more safely.

These pockets vary in size and shape, slope and relation to the sun, thus giving infinite variety in detail to the face of the garden. It would be best that the planting for each area be fairly definite in mind as the pockets are constructed. Though a detailed planting plan for a rock garden cannot be made on paper, the general arrangement of the plants should be decided as the construction proceeds. Surface drainage is another worry at the time of construction.

Most of the rock garden has sufficient slope to carry off excess rain. Too often the little valleys become canyons worn by cloudbursts, when soil and plants are washed away. This must be foreseen and prevented by the laying of the stones. Some of the valleys should have deeper hollows to hold rain for a time, or employ the use of large waterfalls, a patio fountain, or wall fountains, for such rock plants as Primroses and Gentians like their roots well watered.

Actual watering of a rock garden is rarely needed, for with correct construction and proper planting the vegetation will withstand any normal dry season. Sub-irrigation is possible, and at time of construction perforated water pipe or porous drain tiles may be laid among the rocks, about a foot below the finished surface, the upper end to be connected to the water supply for an hour or more in extreme dry weather.