The bright reds, yellows, and oranges tend to excite. The softer blues, pinks, greens, and violets produce a calming, tranquil effect. This is one reason why the monochromatic green gardens of the Japanese are so revered. White tends to be the great unifier, providing a neutral, yet somewhat uplifting spirit. Gardeners need to employ an awareness of color responses when planning the functional needs of garden spaces.
Color therefore contributes to a sense of depth by defining spatial relationships.
Remember too that colors in the landscape are not static, changing with the time of day, cloud cover, and season. Color intensity directly relates to the amount of reflected light. Flower color is transient, while foliage, bark, seed pods, and berries provide color highlights and interest at other times of the year, so must loom large in design considerations. Repetition is the continuing thread in a garden and is generally defined as duplication. Repeating finely textured plants in a garden helps to unify the design and impart a powerful sense of simplicity.