Select a sunny outdoor location with at least 1 square foot of level ground. Pound the rebar into the ground to a depth of 1 ½ feet in the center of the chosen spot.
Place the 12-inch pot over the rebar, through the drainage hole, and settle it on the ground. Put a 3-inch layer of gravel in the bottom of the pot. Fill two-thirds with potting medium.
Place the 10-inch pot over the 12-inch pot, running the rebar through the drainage hole, resting the pot on the potting medium inside the 12-inch pot. Tilt the pot until the inside lip rests against the rebar. Place enough gravel in the bottom of the pot to just cover the drainage hole. Fill two-thirds with potting medium, leveling the soil horizontal with the ground.
Run the 8-inch pot through the rebar. Rest its bottom on the lip of the 10-inch pot below it, not inside the 10-inch pot.
Repeat with each remaining pot in turn, ending with the smallest pot on the top. Place a layer of gravel and potting medium in each pot as you work, tilting each pot in a different direction from the pot below it.
Select plants for the bottom pot. Remove a plant from its nursery pot and settle it onto the potting medium. Repeat with all the plants for the pot, and fill in with potting medium. Tamp down the surface around the plants to firm the medium. Leave 2 inches of space at the top.
Fill the remaining pots with plants as desired. Use trailing, clumping and vertical plants for variety.
Water the vertical garden well to settle the potting medium and hydrate the plants. Care for plants as required according to nursery instructions.