This is so simple, I don't even think I need to use words...
I guess I do now! Ha! Fill your can with potting soil, add wire or ribbon to the side whole. Add plant. and hang!
I am envisioning a whole wall or fence outside, with each can a different size and color! Bonus, I believe if you spray paint the can you don't have to worry so much about rust!
I think I will start saving my cans!