Illinois is the prairie state and Bur Oak is the prairie oak. Very tolerant of heavy clay soil, high pH, and open areas. Bur Oak is bimodal, growing in the uplands as well as the bottomlands. This indicates it is a very adaptable tree. Bur seems to prefer heav ... ier soils to sandy ones, but it definitely needs full sun. One of the fastest growing oaks in our nursery, growing as much as 30 inches per year as a rule. Very asymmetrical in youth, while the rest of the oaks tend to be symmetrical. It becomes more symmetrical as it matures. Bark is deeply furrowed and dark brown. The bark, in combination with the massive branches, makes a very spectacular winter statement.