The Chicago Botanic Garden selected this cultivar for its excellent cold hardiness, surviving 32 degrees below zero with no dieback. Chicagoland Green™ is a broad-leaved boxwood that resembles an English box in appearance. It has a uniform wide-oval habit, good winter color, and is easy to propagate. Grows 3' to 4' in height with a 5' spread in 15 years. Zones 4b-8.