Measure and draw the driveway and planned garden area on your graph paper as close to scale as possible. This initial drawing will help in decision making for soil additives, mulch, types of flowers and plant height.
Decide if you want to remove existing grassy areas completely, or if you'd like to retain some grass on the center island. Grass softens the hard impression of the driveway pavement. Consider removing the grass entirely and making a large garden bed covered in mulch.
Decide if you prefer a symmetrical or asymmetrical garden design. Symmetrical plantings are evenly spaced, match in color and form a pattern within the space. Asymmetrical designs include an off-center focal point or two individual garden spaces separated by patches of grass or mulch.
Evaluate the planned garden area to determine the amount of sun exposure the plots receives each day. Each plant requires specific amounts of sunlight; determine which types of flowers will successfully grown in the sun exposure of your flowerbed.
Determine if you'd like to replant the flowerbed differently every year, or if you prefer to maintain existing plants. Annuals bloom only during the growing season and need replacement every year. Pinch the blooms off annuals to create abundant blooms. Perennials require considerably less maintenance, except if the plants threaten to overrun your garden.
Choose a focal point for the flowerbed. This can be a flowering shrub, ornamental grass, perennial or tree. Build the garden around this centerpiece to draw attention to the garden.
Consider the height of any potential plants in the garden. In general, work from tallest plants at the focal point of the garden to lower around the edges. Plants should complement each other in color and size to create cohesion in the garden.
Use color carefully and in moderation. Pick a few colors and stick with them throughout the landscape to create a sense of uniformity and plan. For example, if you plant around a tree in the center of the circular garden, position taller plants near the tree and work outward in a pattern of plantings.
Visit your local garden center for ideas about the best choices for flowers. Garden centers provide excellent advice on which native plants work best in your area. Remember to check all plant containers for sunlight availability, blooming time, watering needs and special requirements. Remember that this circular garden competes with the sparse expanse of driveway for attention. Choose plants that balance the appearance of this large patch of concrete. In addition, don't choose plants that lie too close to the ground in order to soften the look more.
Select accent flowers that complement features elsewhere in your yard. This continuity of plantings helps the circular flowerbed blend better with the entire landscape. Keep track of your preferences and include all plant choices on your landscape diagram.