For a rhododendron and azalea garden, plan the empty space first. With annuals or low-growing perennials, one's consideration is with the flower bed...but when plants grow tall...such as rhododendrons...it is much better to plan the open area because tall plants will make walls in your garden.

The open spaces will become "garden rooms". Consider traffic flow from one room to another...either by wide connections or with winding paths. Once you have defined the open areas, you are free to plant everything else...as flower beds! Consider how to treat the various spaces defined in the landscape. Should there be "open spaces" to enhance vistas, "corridors" for transitions between area, "closed spaces" for privacy, or "extensions" of the home interior? Consider movement between areas and access routes.

Design for easy care, avoiding plans that require heavy maintenance or constant pruning. Wide paths are better than narrow walks...since the latter often become tunnels over time. If the soil is poorly drained or plants won't grow easily, choose an alternative...such as mulched areas or slate.

Consider costs, too!

There are basic principles in designing. They are:

• Form and Mass. The mature landscape should be in scale with its surroundings. Plants give the garden form, so mass plantings will be more effective than mixed groupings as gardens age. A planting of 5 to 10 azaleas of the same variety will look much better than a mixed planting as the garden matures since the plants will have grown together to look like one large specimen plant.

• Line. Graceful and irregular curves are more interesting than straight line and sharp angles.

• Color and Harmony. Choose colors and varying leave textures that go well together. Color schemes should be harmonious and compliment each other and any existing architecture.

• Emphasis and Contrast. Place light colors again dark ones for emphasis. Include plenty of white and neutral colors to blend or provide transitions. For gardens with brilliant shrubs like azaleas and rhododendrons, it is wise to allow for at least 50% of the plants to be white or other soft tones to allow the eye to have a visual retreat from the more intense colors. In addition to white, pale pinks and yellows...such as those in some of the Knap Hill azaleas like 'Marina' are good blending colors.

• Balance and Repetition. Informal, asymmetrical balance is preferred to symmetry since formal designs with shrubs become a liability over time. A large planting on one side of the yard can be balanced with a small but similar grouping on the other. Repeat colors and forms.

• Unity. Everything should go together. The garden should enhance the home architecture and the community. Simplicity is desirous...but often difficult to achieve for a plant collector.
• Choose varieties that will grow in scale appropriate for the landscape needs. Some azaleas and rhododendrons can be used as ground covers while others will be trees. Use dwarf varieties in the foreground or constrained places. Use large growers in the background or for screens.
• Consider time of bloom. Some varieties flower very early and may need frost protection while others bloom late and might require more shade to extend bloom time.
• Change the color scheme by selecting plants that bloom at different seasons.
• Use many companion plants.