You have to be a bit careful with the name F. dracocephala, as the naming got in a mess. What is usually sold as F. dracocephala, and is what I guess you are talking about, is now correctly called F. apicirubens, though no one in the trade seems to use this name yet. F. dracocephala now correctly refers to a species which includes what is sold as F. rufa, which should now correctly be called F. dracocephala 'Rufa'. You don't want to mix these two up, as F. d. 'Rufa' is a mini-bamboo that only grows to about a metre tall...