I had planted them in a bed together but believe that was a mistake, as they are very crowded. If the plants need to be moved due to overcrowding, you can also do that this fall, Plants that bloom in the summer can be divided spring or fall. Fall is ideal since they produce a stronger root system during the winter. My cannas have grown very tall. I see at some homes they are only about 3 ft. tall.
Different varieties grow different heights.
Also, type of care or location can also determine more or less growth. If they are in a rich, moist environment, they typically do better than if they are in a poor, dry site. The Arkansas Cooperative Extension Service offers its programs to all eligible persons regardless of race, color, national origin, religion, gender, age, disability, marital or veteran status, or any other legally protected status, and is an Equal Opportunity Employer. The mention of any commercial product in this web site does not imply its endorsement by the University of Arkansas Cooperative Extension Service over other products not named, nor does the omission imply that they are not satisfactory.