Five disease resistant varieties of flowering dogwood (Cornus florida), released by the University of Tennessee in Knoxville, are available at local garden centers this spring. Supply should be better than in past years. Powdery mildew resistant varieties: ‘Appalachian Snow’ (pictured), ‘Appalachian Blush’ and ‘Appalachian Mist’. In addition, ‘Cherokee Brave’, with dark pink flowers, exhibits good mildew resistance. […]