Courtyards are found all over the world, and have formed the basis for thousands of years. For example, the heart of a Roman house (the central open courtyard or atrium), had an enclosed hortus (garden) off it. The great Islamic gardens of the Moors and the Persians, like the monastery gardens of Europe, were set within enclosed courtyards formed at least in part by the surrounding buildings: walled enclosures that provided protection from the elements and from attack.

Today, the real requirement of a courtyard is that the area should be enclosed by walls, often those of the house or surrounding properties. Since these courtyards are often not very large and, being protected by walls, have a climatic advantage over nearby areas, they make ideal outdoor rooms. The best courtyards take full advantage of this, with plenty of room for sitting, barbecuing, dining, and relaxing.

However, one of the important principles of design states that the smaller the space, the more you have to pay attention to the details. This is because everything is close to hand and easily seen. In terms of fencing or walling, this will mean that not only is the choice of materials important, but also the manner in which they are used. Hard surfacing is an important factor, and this should be planned to provide a positive link with the interior of the house itself, such as continuing an indoor colour scheme to the outside, or laying paving to match the floor inside. Overhead beams running out from the house can provide dappled shade, as well as support for fragrant climbing plants. They may also provide privacy, and screen your garden from neighbouring windows, and act as a ceiling for your outside room.

Courtyards are not necessarily rectangular, and many are formed in the angles between adjoining buildings. Interesting shapes like this offer all kinds of appealing design possibilities, including the chance to create a variety of features such as built-in seating, raised beds, lean-to buildings and conservatories, as well as a wide range of water features.

Fragrant plants are indispensable in a courtyard, as the still air traps scent. This includes climbing plants such as jasmine, night-scented annuals such as flowering tobacco (Nicotiana) and evening scented stock (Matthiola bicornis), as well as an enormous range of scented plants for pot. Herbs are an excellent choice where a courtyard leads off from the kitchen.

Thanks to its protective walls, the microclimate of a courtyard is often very mild, which may allow tender climbers to be planted. However, since heat may be intensified within the walls, drought and heat-resistant plants may need to be chosen. In courtyards with solid walls on all (or especially the windward) sides, damaging eddying winds can be a problem. If so, sturdy climbers should be chosen, and fastened securely to the walls. Pots should be kept out of very windy spots, as otherwise the contents will dry out quickly.

However, in general, plants tend to flourish in courtyard gardens. There is much less likelihood of neglect as they are always on view. Since courtyards tend to be thoroughfares as well as seating areas, they are usually kept neat and tidy, and the plants dead-headed and in good condition.