The principles for planting these containers are the same; only the plant combinations change.
Choose a pot that's 18 to 24 inches in diameter and at least as deep. Steeb favors thick-walled plastic ones, which hold moisture better than terra-cotta, provide good insulation against heat and cold, and weigh less than terra-cotta, ceramic, or cement. If you buy containers without drain holes, drill two or three 1-inch holes in the bottom of the container.
Also buy a bag of rich, fast-draining potting soil. Since potting soil quality varies so much from brand to brand, and brands vary from state to state, ask your nursery for a recommendation. If they say they're all the same, find a better nursery.
For a finished look from planting day forward, use only perennials from 4-inch and 1-gallon nursery containers.
Pour potting soil into each container until it comes to within 4 inches of the rim, then firm it; Steeb steps into the pot and stamps the soil with her feet. Sprinkle timed-release fertilizer onto the potting soil. Use an extended release formula: Six or nine months is good.
Wearing gloves to protect your arms from thorns, arrange the plants - still in their nursery pots - on the soil; experiment with different combinations to see which foliage textures and colors work best together. Place taller plants at the back or - if the finished pot is meant to be seen from all sides - in the center. Put trailing plants along the edges and use intermediate plants as fillers.
Once you have the plant combinations worked out, remove each plant from its pot, rough up the rootball, and plant, packing the soil around the plant. Water well; add more soil if rootball settles (soil level should be about 1/2 inch below the container's rim).