Flower garden designs include formal beds arrayed in straight lines and geometric shapes to informal cottage gardens with a mix of heights, shapes and textures. Regardless of your desired aesthetic outcome, planting without planning can lead to an unattractive jumble. Choose flowers that complement each other in color, height and texture, and in blooming time, to create a pleasing floral display throughout the garden season.
The eye sees color first, as we are reminded by the University of Illinois Extension in their comprehensive website Stepping Stones to Perennial Garden Design. The Illinois extension adds that research has shown that people are most attracted to either closely harmonious colors, or sharply contrasting colors. Blues planted with gold or oranges make a traditional complementary contrast, and can include Siberian iris planted with black-eyed susans, delphiniums interplanted with yellow-flowering yarrow cultivars, or on a more diminutive scale, yellow ground-cover sedum varieties with purple pansies and blue forget-me-nots. Impatiens, petunias, and salvias make complementary interplanted annual beds with strong color-wave potential, such as a planting of related pinks, reds and oranges.
Height and Texture Combinations
Plant heights that descend toward the front of the garden allow all your flowers to be seen, while texture choices can include all soft-looking plants (artemesia, bunny-tail grasses), all spiky plants (yucca and echinops) or a combination of effects to keep the eye moving around the flower bed with visual interest. Norman Winter, a horticulturalist with the Mississippi State University Research and Extension Center, recommends a dramatic combination of tall purple fountain grass, upright blue Mexican petunia and a chartreuse sweet potato vine in the foreground. These plants have descending heights and contrasting textures, which make the combination appear to be reaching out to the viewer.
To maximize your flower bed impact across the growing season, consider flowers that complement one another in successive waves of blooms. Sedum and yarrow plants provide attractive foliage early in the growing season, but do not bloom until August and early autumn. This makes them quite complementary to a succession of spring and summer bulbs, such as crocus followed by daffodils, tulips and iris. Consider including flowers of similar color and growing habit, but with successive blooming times, to occupy a particular visual focus in the flower bed. For example, delphiniums and monkshood bloom with complementary tall blue spikes, with the delphiniums coming in mid-summer and monkshood blooming slightly later and lasting until a hard frost.