The Terra Cotta Pot Flower Tower is made by using terra cotta pots in descending sizes, stacked on top of one another. The tower of pots (anchored together by a long pole or dowel rod) allows you to plant terraced rows of flowers that cascade downward.
Disney world does this! Lowes sells the 4 to 6" round PVC pipe with holes already drilled. Purchase an end cap, fill with rock, soil, and plant. Can also put these in the center of a very large pot to stabilize, and add amazing height and color to a container that has trailing plants (no end cap or rock needed if you are placing in a container)