Changes of level, even relatively small ones, can provide interesting features in a garden. A well-planned sunken garden can add a feeling of adventure and space, as well as bringing another dimension to the design.

Traditional sunken gardens were usually rectangular or square, enclosed by walls, and bordered by paved paths or raised grass so that they could be seen from above. The layout was typically simple and geometrical, with flowerbeds divided by a symmetrical framework of walkways and paths, perhaps with a central sculptural feature, such as a sundial or fountain.

As they are lower than the rest of the garden, sunken gardens are often secluded and sheltered, with a secret, sanctuary-like quality that is particularly restful and appealing. Formal bedding, herbs, and roses lend themselves particularly well for use in sunken gardens.