Oooh, they are in 6 inch pots and are 2 feet high!!? Wow, that is a small pot size for such a large plant. I don't know if this would stop the buds from forming, but it sure might. Has the plant grown at all since it reached the 2 foot mark. If it hasn't, then you are probably right and that is most likely your problem. The growth has stopped because there is no more room for root development.