There are four types of color schemes: monochromatic, analogous, complementary, and polychromatic. If you are new at designing with color, your chances of success will be greater if you restrict yourself to one of these color schemes.
Monochromatic colors
This color scheme consists of the various tints and shades of one — and only one — of the pure colors (a hue) on the color wheel. (A tint is lighter than the pure color, and a shade is darker.)
Some of the most impressive flower gardens are planted in a monochromatic color scheme. An example would be red, various tints of pink, and a deep shade of red, or maroon. Visualize a flower border planted with maroon snapdragons (Antirrhinum majus), red and rose-colored nicotiana, and pale pink dianthus, and you can begin to see the possibilities of such a color scheme.
In reality, there are no totally monochromatic gardens; the various shades of foliage and bark are always part of the combination, although their presence is a pleasant one that usually does not detract from the more predominant flower colors.
Analogous colors
This scheme makes use of neighboring colors on the color wheel. Any three colors used in the same sequence in which they are found on the color wheel are said to have an analogous relationship. An example is blue, blue-violet, and violet.
To expand the possibilities of such a color scheme, you can include the tints and shades of each of the colors. Because you have more colors to choose from, an analogous scheme is easier to work with than a strictly monochromatic one, and the results can be memorable.
The English writer and gardener Gertrude Jekyll developed what she called a tonal garden, based on rules similar to those for an analogous color scheme. In the best of the gardens designed by Jekyll, all the colors, including leaf color, are tonally related. One garden (Folly Farm in Berkshire, England, which was planted at the turn of the century) made use of silver-leaved plants and white, pale lavender, and ivory flowers. The colors of the foliage and flowers in turn complemented the colors of the stone walks and walls.
Complementary Colors
This scheme consists of two colors that appear directly opposite each other on the color wheel. These are powerful combinations: red and green, orange and blue, yellow and violet, and so on.
For the maximum effect, the purest hues (rather than shades or tints) should be combined. If you want to balance complementary colors, you will need four to five times as much of the cool color as the warm color. Some people might say that complementary colors clash; others find them vibrant and vital.
Often these combinations are predominantly displayed in parks and other public areas. They are not always the best choices for a small garden. Confining a powerful color scheme in a small space intensifies its effect and can make it overwhelming.
If you want to try to blend strong complementary colors, place the plants so that they intermingle where they meet, rather than clearly defining the juncture. Intermingling colors in this way enhances their vibrancy, and from a distance they will appear to blend somewhat at the edges. You can always tone down the colors with silver-leaved or white-flowered plants.
Polychromatic Colors
This color scheme, which combines any and all colors, can produce a carnival-like effect in the garden. An English cottage garden, with its riot of color, is an example of a polychromatic scheme. In most cases, however, this type of color scheme is the result of the gardener’s inexperience rather than a conscious design.
There is nothing wrong with a polychromatic color scheme, and some gardeners prefer it because it mimics nature. One benefit of random planting is the possibility of happy accidents — color combinations that you would never think of but that work well.