At the University greenhouse, we rarely have clips for plastic pots, so have to get ingenious. One of our favorite tricks is poking two small holes in opposite sides of the pot near the top of the potting media level. Then taking a small florist type wire that's about a half inch longer than the diameter of the pot. Then bend a small 'L' on one end of the wire before feeding it through and capturing the roots or rhizome before going out the other hole. Pull it tight and bend the wire against the pot. Voila!
