Plants can be grown in all kinds of containers, limited only by your imagination. You can use traditional wooden tubs or barrels, clay pots and even old children's toys such as wagons to nice effect. Design your container garden to match the style of your landscape, whether that is formal, contemporary, eclectic or country. Garden containers need only be deep enough to accommodate plant roots and have adequate drainage.
Decide on the purpose and location of the container garden. Do you want a functional container garden to grow herbs or edibles? Are you highlighting an area of the landscape or beautifying a dull corner of the yard? Do you need to cover an obstruction like a utility box or create something visually pleasing to see from the patio or kitchen window?
Select containers. The purpose and location of the container garden dictates the required size of containers. The aesthetics of the container(s) will suggest the desirable characteristics of the plants you choose. Attractive or interesting containers should still be visible when filled with plants. Less attractive containers call for plants that spill over the edges and partially or completely obstruct the container itself.
Choose a color scheme. The color of flowers and leaves in your container garden design can be monochromatic (using different shades or tints of one color), complementary (using colors from opposite sides of the color wheel) or analogous (using colors that are next to one another on the color wheel). No color scheme, just using a random assortment of plants, may look natural but is not as aesthetically pleasing to many people.
Choose a visual line for the container design. A single large container or a grouping of containers can have a balanced line like the normal distribution curve with the tallest containers and plants in the middle and shorter containers and plants balanced on either side. Or, you can use an straight line with tall plants on one side and progressively shorter ones from the middle to the other side. For long containers you can use two high points---usually one higher than the other---at either end of the container with lower-growing plants in between.
Use differences in texture to make your container design interesting. Fuzzy Lamb's Ear, rough edged geraniums, fluffy fountain grass or spiky dracraenas provide interesting shapes and textures for a container garden.
Select plants. The plants should be adapted to your growing region and conditions. The tall plants should not be more than twice the height of the container. Side growth should be equal to or no more than 50 percent broader than the container.
Place plants into the container. First, see where the "front" of the container will be. This is based on placement of the container relative to fixed features and viewing angle. Place taller plants first and toward the back based on the chosen visual line and then add the middle-sized plants and finally the smaller fill and weeping plants toward the front.