Designing a garden with plants exhibiting many different colors requires some coordination. Consider the color of the house and any other fixed structures such as fences or utility buildings. Using pink flowers against a brick house with orange tones would not produce a pleasant combination.
Try to use masses of a single color instead of mixing colors in a flower bed. A mass planting of a single color or planting in bands of colors will produce a stronger impact.
Consider location and how the flowers will be viewed. Bright colors stand out, while dark colors fade into the background. For example, a bed of red flowers can easily be seen from a distance, but blue and purple flowers can only be enjoyed up close. Bright colors draw attention to an area, so do not use red and yellow flowers near an eyesore or unattractive area. Bright colors appear closer, while dark colors make the area appear further away. White is the last color to fade from sight as darkness falls and thus is good for areas used at night.
Colors that look good together are said to be in harmony. There are four basic color schemes to choose from: complementary, monochromatic, analogous, and triadic.
Colors also have an effect on how people feel. Colors on the right hand side of the color wheel are considered warm colors (yellow to red); colors on the left side are considered cool colors (green to violet). Planting warm-colored flowers around a deck or patio will make it seem warmer. Red tends to excite people. Research has also shown that food tastes better around red colors. Pink is perceived as being sweet and fragrant. Yellow is associated with liveliness and exuberance. White gives the feeling of neatness, cleanliness, and orderliness. Green is a color that helps eyes recover quickly from strain. Blue is perceived as cool and calming. Gray is said to promote creativity.