Here in N. Illinois, the hardiest variety I am aware of is Top Gun and sown from seed in May. As you know Buffalo Grass is a warm season perennial, greening up late and going dormant early. Plugs seem to be available from a number of places, variety or cultivar would be your main concern. Many are not going to be winter hardy. Please contact the Iowa State Extension to determine of there is a variety that does well in your part of the state.
