Any outdoor space that one can accessorize either as an useable space (for an activity) or more simply as a visual focal point.
Know the area you are designing for. . . the sun aspect, shade factor, existing trees, slope, drainage and amenities. How close to the house, garage, outbuilding or shed, neighbors fence or wall are all important things to consider. You wouldn't want to design a quiet reading room next to the neighbors swing set, or facing the setting sun if you read mostly then, etc.
BORDERSEach room has its own character, but need to be unified by the walls that contain it. Using the same plant for a hedge as well as a free-form background shrub in another area will accomplish this. Fences and low walls work well as visual barriers, and can add interest by the materials and colors selected, but will become accent elements and should be used as such. Too much going on in this scenario creates visual overload.
DESIGNTreat your outdoor room as you would your living space inside your home. The only difference being that items one uses there need to be able to endure the weather. Some rooms can be designed to be used actively for a short time and still look good when not in use; storing the furniture, umbrella or canopy when not in use. One could design an outdoor reading room, under a nearby tree with a gravel floor and an Adirondack chair. The room could be delineated by a clipped hedge, a low wall or decorative fence - all depending on your own style of landscape.
Plan out your garden room by creating combinations of spaces linked by pathways. The sizes and shapes should vary to create interest. I usually like to maintain a line of sight or partially obscured vista of another 'room' in the distance to keep one moving to the final destination. Keep in mind that you never want to see the whole garden at once. It's fun to be surprised and have different views as one goes through the garden. Rooms in the garden don’t have to be very large either. You can make a very small space (10 x 10 foot area) appear to be larger by using elevation changes. A simple step up or down to a room creates drama and a sense of volume in the room. Adding levels with tables and pottery or statuary accents add to this feeling, as well as giving the space a completed look
TIPSDefine your spaces to fit your personality. Weather tis a quiet reading room, an area to stretch out on a hammock, or a place to set up a rustic table for a twilight dinner party, its completely interchangeable.
Limit the kinds of plants used in each room. Try to use 5 or less in one area, and repeat some of the background plants throughout the entire garden.
Create focal points that can be seen or partially seen to add intrigue. Pottery groupings, statuary, lights or a planted arbor are some examples.