Yeah I was the same with my white habs last year......Very slow and sickly to start with but then they take off and you can't stop them...
I'm not a big fan of the taste though. I'm growing them again this year cause I plan to make an all white chiil sauce...or as close to white as I can get it.
Great looking White Hab plant. I too was amazed about how productive they were. Mine never got as tall as your plant though, but they are loaded with pods so I can't complain.