Korean mountain ash (Sorbus alnifolia) has a broad, rounded shape, and can attain heights of 35 to 50 feet. This tree is a great specimen plant for the home landscape. A member of the rose family, this small, flowering tree displays clusters of white, five-petaled flowers in May. Red-orange fruits ripen in the fall and persist into the winter season. Its fall foliage is attractive, with leaves turning to copper, orange, yellow, and red. Korean mountain ash has interest in all four seasons: attractive flowers in spring, good clean green foliage for summer, handsome red fruit and great color in fall, and nice gray bark for winter interest. It's the best mountain ash for Illinois.