According to a page from Southern Living magazine, Bitter panic grass and serveral other grasses grow "34 feet tall" http://www.southernliving.com/plants...ss-panic-grass .
Of course, this must be a typo for "3 to 4 feet tall". Since everything we read on the internet is supposed to be true, I emailed Southern Living about this error. It will be interesting to see how long it takes for them to correct it.