I think bamboo is great for something like this. In a container, you don't have to worry about "spreading." Advantages: frost-hardy (depending on the variety up to -20°), evergreen, looks nice, meditative rustling in the wind. Disadvantage: needs a lot of water, too much sun is not good for most varieties, doesn't like too much wind either. My current neighbors in the penthouse basically have a bamboo grove on their rooftop terrace. It always makes me envious when I look at it through the stairwell window.