Balancing Your Potted Plant Display
All gardening is a glorified form of flower arranging; this is particularly true of potted displays, where you need to think about the look of the containers as well as the plants.
From: DK Books - Containers for Patios
Potted plants are incredibly versatile. Use them as stage props, helping to offset and/or highlight major features such as this wirework gazebo (below). The symmetrical pots embellish its bare legs, but you could go further and use climbing roses to cover the roof, and morning glory (Ipomoea) twined up the front two posts.
Plants as Sculpture
Try copying the Chinese and Japanese and use a few beautiful, shapely plants to create an eye-catching picture.
Rhythm and Order
Repeat planting—and that applies to both containers and plants—has many advantages. It creates a formal, organized look, especially with topiary cubes and balls, and lends itself to echoes. Repeat planting can also propel the eye in a certain direction, either drawing attention to a display, or diverting the focus away from eyesores.
Scale and Proportion
Place a potted plant combination within a context, such as these two framing pillars. The pink masonry picks up the color of the osteospermums, while the container is large enough to take center stage. White gravel sets off the pastel theme.