I did some looking around, Karen, and the general consensus is that it grows to about 30", and looking at the pictures, that seems about right. It does appear to be a perennial, but it sounds like you may not see flowers till the second or even third year. I see what you mean about conflicting information, tho!
This is some information from a growing trial, in case you didn't come across it yourself:
http://www.ncsu.edu/project/cu...
