Thanks everyone for the tips and links! This is the very first Gomphrena I have ever purchased so more info is welcome.
Since there really is no definitive answer on propagation, can someone tell me what the habits of Gomphrenas are in general? i.e. Is it a spreading plant? If so I can try repotting into bigger pots and propagate by division of root stock. Unless of course this is a short-lived plant!