Expert tips. It helps to plan the design on paper and then tweak it at planting time. Or try different plant combinations on a wagon at the nursery.
Foliage. Structure, texture, and movement are supplied by foliage plants. If you match one strong foliage plant with one long-flowering annual or perennial, you have the basis of a good container planting, says Erchinger. Davis-Thomsen likes to use oversize nursery stock for her dominant foliage plant―a 5-gallon Phormium, for instance. For the remainder of the planting she would use 4-inch pots or smaller.
Container. Choose a pot that suits the architecture of your home and the colors in your garden (including paving material); it should stand up to your climate. Then let the pot determine the overall look of your planting. Use large containers (at least 22-in. diameter) to maximize impact. Drill a drainage hole if your pot doesn't have one.
Soil. Use a high-quality potting soil. Fill the container about 3/4 full, mix in controlled-release fertilizer, and lightly wet the soil.
Plant placement. Start with the central, most dominant plant, then work toward the outside of the container. When you're done, pack soil between the rootballs. To allow for adequate watering, there should be at least 2 inches between the top of the soil and the pot's rim.
Water. Because dry plants attract insects and go out of bloom faster, many designers specify drip irrigation timed to water each container daily. If you don't use drip, add a water-absorbing polymer to the soil at planting time and check soil daily, watering before it dries out completely. Always water under the leaf canopy to keep the leaves dry.
Fertilizer. After planting, apply liquid fertilizer every two weeks.