How to Make a Rock Garden
Remember,is critical, so unless you are building your rock garden into an existing steep slope, chances are you will have to improve the bottom drainage. To do this you must excavate the site of the new rock garden to a depth of about 25 cm/10 in and then backfill with a 10 cm/4 in layer of rubble, over which you spread a 5 cm/2 in layer of sharp sand. Top off with a 10 cm/4 in layer of clean topsoil.
The easiest way to make a rock garden on a flat site is in a series of tiered. Place the stones carefully, making sure that markings and so on fall naturally; butt the stones up against each other and bury them into the prepared site by about one-third of their total size. Try to make the stones look as though they were being pushed up out of the . They should also tilt back slightly, rather than lay flat. Fill in and around the stones with prepared compost, firming the soil well into place. Repeat this process with the remaining tiers, partially burying each stone and firming the soil well to ensure there will be little or no movement. When you have completed the construction, water the rock garden well and leave for a few days before planting. This will allow the rocks and compost to settle and permit you to top up with compost before planting.
The only planting that you should do as you progress is that of crevices and cracks created where the stones butt up against each other. It is not, by any means, desirable to plant every one of these, but do use the opportunity to cultivate a few specimens, such as sedums and sempervivums.
As 1 mentioned before, the ideal rock garden is one built into a slight slope, but unless this slope is composed of free-draining, sandy soil you will still have to improve the drainage conditions by excavating. Begin work at the top of the slope and work downwards to make the task easier.