Rock gardens are particularly suitable for sloping ground. Here the stones can store heat across their full surface and consistently dissipate the warmth to plants close by. (Stones are also eminently suitable for laying along the edge of a path or on a patio.)
Remove approximately 30 cm soil and any roots, to prevent weeds coming through later. The material removed is mixed with crushed stone and sand and refilled to 25 cm. In order to avoid waterlogging and to provide stability for the heavy stones, add a top layer of gravel. For additional protection against root voles, lay chicken wire between the crushed stone mixture and the gravel.
A rock garden obtains its charm by looking as though it has been generated purely by chance. For this reason, do not work with different kinds of stone, but only using stones of the same type. Sandstone, basalt or granite are for example highly suitable for plants which dislike lime. Limestone and travertine, on the other hand, harmonise well with plants which like lime. Now the stones can be embedded with their larger surfaces facing downwards. Try to emulate Nature. This means that larger stones should be positioned lower down the slope, lying on top of each other and sunk in between small stones. Fill in any hollows between the stones with a drainage layer of gravel or sand, thus preventing waterlogging and fixing the stones in place.
Apart from that, there isn't a lot to observe when using stones. Simply use your imagination and arrange the plants accordingly!
Plants which enjoy dry and sunny conditions are particularly suitable. These include thyme, thrift, bellflower and edelweiss, but also trees such as box and mountain pines. Use low-growing plants, otherwise the garden can appear overcrowded. The plants are planted at the appropriate points.
Ask at your garden centre about suitable plants and their requirements.
During the first year, you will have to water the plants regularly, as they have yet to grow substantial roots. From the second year onwards, the plants require almost no water, except during severe periods of hot weather. Due to your correct garden preparation, hardly any weeds will appear.