Purple nierembergia is wonderful planted with the deep yellow Dahlberg daisies. Harmonious colors are next to each other on the color wheel. Examples would be combinations of red with purple or orange, blue with purple or green, yellow with green or orange, or orange with yellow or red. These plantings are not as vivid but have a more softening effect. This is why red geraniums look at home surrounded by violet and pink lobelia or alyssum.
Monochromatic plantings can also be quite attractive.
These color schemes use different flowers in a single color throughout a flower bed. For example, an all-pink garden might use pink geraniums, petunias, verbena and vinca. The different hues and forms add interest and appeal. After determining the colors needed to fill the design, calculate the amount of flowers by counting the number of squares on the graph paper in any color. Most annuals are planted on about one-foot centers.