HO-185
LANDSCAPE ARCHITECTURE
Color as an Element of Planting Design

LANDSCAPE ARCHITECTURE • COOPERATIVE EXTENSION SERVICE
DEPARTMENT OF HORTICULTURE • PURDUE UNIVERSITY • WEST LAFAYETTE. INDIANA
by Ada Niedenthal

Everyone is aware that flowers contribute color to a landscape. While flowers do produce dramatic effects, the color statements they make are necessarily short lived. Since plant foliage is present during the greater part of the year, the color characteristics of foliage are very important in planting design. In addition, other plant parts, such as fruit and bark, also contribute significant color throughout the year.
Color is, of course, only one of the criteria to be used in selecting landscape plants. Other criteria, such as the plants’ adaptability to climate, sun, shade, moisture, and soil type, should be considered first. Once those specifications are met, however, the next consideration is the visual contribution color can make to the .landscape.

Color Characteristics
When selecting plants for their color contribution to a landscape, the color wheel is a useful aid the gardener can consult (see Figure 1). With a color wheel the gardener can begin to determine the color characteristics that are most helpful in planting design.
The colors we see are light rays that are reflected from a colored surface back to our eye. Light rays produce colors that are called primary: red, yellow and blue. Mixtures of these primary colors result in secondary colors like green, orange, and violet, and tertiary colors like blue-green, red-orange, etc. The colors on the color wheel are arranged to illustrate this concept. For example, mixing red and yellow results in orange, and these colors are adjacent on the color wheel. They are called analogous colors.
Analogous colors are those most likely to harmonize with each other. This is because of the basic hue which they have in common. When used together, these colors have a similarity that helps to create unity in a landscape.
Complementary colors are those across from each other on the color wheel. When these
colors are next to each other, the result is one of strong visual contrast. The degree of contrast, however, depends on the intensity of the individual colors. The intensity of a color is a measure of its purity. For example, while the foliage of most plants is dominated by the color green, foliage colors range from greyish-green to blue-green to yellow-green. The purer the colors, the more intense they appear. The reddish orange colors of fall foliage as seen against a clear blue sky are an example of intense colors in contrast with one another.
Colors are also classified as warm or cool, depending on their hue. Warm colors, appearing on the right half of the color wheel, range from yellow through orange and into red. These colors are considered bright and lively, and they tend to advance visually and to stand out. The colors ranging from green through blue and into violet are called cool colors. Cool colors are considered more restful; they tend to recede visually and are generally not as conspicuous.

Effect of Color Schemes
Careful selection for color in planting design can enhance the colors in the surrounding architecture. For example, architectural brick is available in a variety of colors. By carefully examining the bricks, one can pick out a predominant color and then accent that color in the surrounding landscape. If the predominant color in a brick building is observed to be in the red-violet range, then plantings of purple-leaf varieties might be used to strengthen that hue. Contrast would be achieved with plants in the yellow-green range.
While contrasting colors can be used to attract attention, these colors should never clash. Bright green foliage commands attention, and when used next to a yellow house, can complement the architecture. But other contrasting combinations may attract undesirable attention. For example, using red foliage plants