To brighten shady areas use light colored plants such as white, light pink or palest blues. Dark colors tend to get lost in shady areas. Dark colors can be used in shady areas, just be sure to use lighter colors around them or as a background to make the darker colors stand out. Burgundy impatiens surrounded by pale green coleus or coral impatiens, for example, will stand out due to the contrast.

For maximum effect, think about how the colors of the plants or flowers will blend or contrast with their surroundings. For example, deep red geraniums or red salvia planted against a red brick or redwood fence will not stand out as well as white or pink geraniums. And white geraniums will not stand out dramatically against a white fence or white siding. Think of using a more dramatic color scheme such as purple or magenta against white or light-colored backgrounds and something lighter, such as peach or pink against darker surfaces.

Just as interior decorators use three or four colors as a theme throughout a home, "exterior decorators" can do the same. Theme colors used with repetition will unify different garden areas just as they unify the rooms of a house. For example, bordering all your garden plots with a row of yellow marigolds or creamy petunias can tie different garden areas together for a unified look. Repeating the same colors but in different plant types can create the same effect. If white and blue are your colors, for example, plant different types of flowers such as lavender, blue petunias and blue salvia, and for white use white geraniums, white impatiens, white petunias, etc. to carry the theme but vary the look.

Just as each room should have a focal point, so should each area of your garden. If there isn't a natural focal point such as a pool of water or garden statuary, color can create one. Instead of long, uninterrupted row of flowers, create a focal point by planting a mass of one color in the center of a bed and then surround it with flowers or plants that contrast in color, texture or height. If there is something unsightly in your garden that you can't get rid of and really can't hide (like a telephone pole or a fire hydrant), create a colorful focal point away from the object to draw attention in that direction and lessen the effect of the "problem" area.

Colors affect our emotions. Bright colors such as red and yellow excite us and can make us feel warm (that's why they are often called "hot" or "warm" colors). Colors such as blue, lavender, green, pink and peach are considered cooler and calmer. For the entrance to a home, you may want to create a feeling of warmth and excitement, and could choose stronger, more exciting colors such as yellow marigolds and scarlet dianthus. In the backyard garden or for patio containers, you may want to create a more relaxing and serene mood by choosing cooler or softer colors such as pansy rose shades with blue violas.

Dramatic color combinations can give your garden beds a distinctive look. Instead of something as ordinary as red and white, consider orange and blue (direct complements on the color wheel), or light pink and green.