Rock gardens and rockeries are intended to look like naturally formed rocky features, and can be an eye-catching and attractive addition to any garden. To look as natural as possible, they should be situated on a sloping, open site; one that faces south or south-west will provide a sunny aspect that will suit most rock plants. Those that prefer shade may be grown in cooler, shady pockets on the north side of larger rocks.

You will need an area of at least 2.5 by 1.2 m (8 by 4 ft) to make a worthwhile sized rock garden, although you should aim to use as generous a scale as the site allows. An effective design will include a series of rocky outcrops with gullies running in between, possibly with a number of streams or pools. However, it will be impossible to plan the positioning of the stones accurately at the design stage, as the rock itself will determine the exact outline and final arrangement.

Site Position

Your rock garden should preferably be in the sun for the majority of the day, and so a south or south-west facing slope away from any shade casting trees would be ideal. Not only will this provide a natural looking backdrop, but will also offer excellent soil drainage, which is essential for alpine plants. Although rock gardens may be built in flat gardens, they can sometimes look slightly unnatural and so a raised bed may be a better idea for these sites.

Avoid choosing a position near trees as their roots will compete with the plants for nutrients and moisture. Deciduous trees will also shed leaves over the area in autumn, which may smother plants or produce a damp environment that will cause them to rot. You will also need to avoid frost pockets and sites exposed to cold, drying winds.

Design Considerations

When planning the position of your rock garden, try to ensure that it blends in well with the rest of the garden. You can create a feeling of open space by siting the rock garden so that a distant view is visible beyond it. Alternatively, in small gardens, create a more natural look by using climbing plants to conceal any walls or fences that back onto the rock garden.

Rockeries rarely suit very formal gardens, and can often look quite out of place. It may be better use a raised bed in these situations rather than trying to force the informality of a rock garden into such a formal space. If you want the rock garden to look natural, you will also need to avoid siting it too close to other formal features in the garden, such as bedding displays or herbaceous borders.

If you are planning to build a large rock garden, make sure that you include paths or stepping stones to provide easy access for planting and maintenance.

To help you visualise the garden, you may find it useful to make a rough scale model, using small stones or polystyrene to suggest outcrops. The aim is achieve a natural effect, simulating valleys and cliffs along natural stratum lines. Use this model to plan your planting, taking into account the height and eventual spread of each species.