Before starting to plant your garden you need to ensure that the soil is well-prepared and has enough nutrients to keep plants healthy. When you plan your summer flower beds, be aware of how much sun is available in different areas of the garden. Note the shadows cast by fences, walls and buildings and amend your plans accordingly. "Drift" or swath planting the flower beds will give blocks of color that are pleasing to the eye and provide excellent foraging for honeybees. Determine your U.S. Department of Agriculture plant hardiness zone to give you an indication of whether plants will survive in your locality. You might also check out local gardens and parks to see the types of plants that thrive in the area.
Unless you are planting an island bed, which is great for all-round viewing, you will want to plant taller flowers at the back of your border. Some flowering perennials that are ideal for the back of the border include astilbe, iris, bee balm (Monarda fistulosa), black-eyed Susan (Rudbeckia hirta), Shasta daisies (Leucanthemum superbum) and daylilies (Hemerocallis). This selection of flowering plants is hardy through most of the U.S. Department of Agriculture plant hardiness zones and will provide color from early summer through fall. A variety of spring-flowering bulbs in the back of the border will add more color and give interest to the flower garden for most of the gardening year.
Smaller plants should be placed at the front of flower borders. Some classic summer-flowering perennials that are ideal in afternoon sun borders are hybrid anemones (Anemone x hybrida), which are hardy in USDA zones 4 to 8, carnations or pinks (Dianthus) which are available in a number of varieties and USDA hardiness zones, and hardy geraniums or cranesbill (Geranium "Terra Franche," which will thrive in any USDA zone.
Once you have planned the basic flower garden layout, you can add a variety of colors and shades with summer-flowering annuals, pots, planters and colorful spot plants. Check out the best-performing annuals in your locality in parks and open spaces, then add drifts of color or spots of accent color to specific areas of your flower bed. Some of the popular annual plants that are hardy across most U.S. planting zones are petunias (Petunia x hybrida), African marigolds (Tagetes erecta), annual vinca (Catharanthus roseus) and annual phlox (Phlox drumondii).