According to Michael Dirr - a "vigorous selection from Gulf Coast with good heat tolerance. Flowers large with a mix of showy sepals and fertile flowers."

I'd take the word "vigorous" to mean it should achieve a size comparable to the species - 8-10' tall in time and as wide. Dirr declines to state sizes unless it is markedly different from the growth habit of the straight species. Ultimate size of any plant will be determined by growing conditions, but I'd expect it to get big.