I use all different types. Terra Cotta, glazed, plastic. Terra Cotta can be an issue in extreme heat, but then so can black plastic pots. Shapes and sizes will depend on the width of caudex and root system. As long as they have plenty of drain hole in the bottom, all will work.
Rick
"Many times a day I realize how much my own outer and inner life is built upon the labors of my fellow men, both living and dead, and how earnestly I must exert myself in order to give in return as much as I received"
crystalview said:Opps typed that wrong. The shape of the pot helps when you up-pot. Your not pulling to hard to get your plant our of a smaller area then the opening.