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.
Repetition is simply a matter of holding one design quality constant while varying the others.
Variety is the life of the garden. The design qualities of line, form, texture, scent, and color are changed and contrasted to provide diversity and avoid uniformity. Diversity develops a tension which helps to hold the observer's attention while creating excitement and enjoyment. Variety is the opposite of repetition. But when it is overdone by adding too many elements, chaos results, so a very fine balance between repetition and variety is needed to achieve unity in a landscape.