River Birch 'Cully' Characteristics
Much of the interest of 'Cully' comes from the peeling bark. The outer layer can be anywhere from a salmon color to brown which exfoliates to reveal a white interior. When grown with a single trunk, the shape is naturally pyramidal or rounded. When grown with multiple stems, the shape becomes more irregular. Muti-stemmed shapes are considered to be healthiest for this cultivar.
River Birch prefers the cold weather of the North American north and does not survive well in the hot summers of the southeast. When they are weakened by heat, they become susceptible to the birch borer which can kill the tree. 'Cully' is particularly resistant to birch borer and leaf spot, making them a viable and low maintenance option in the Pittsburgh climate.