Big-leaved hydrangea (Hydrangea macrophylla): This shrub from Asia is a classic in east coast gardens. However, big-leaved hydrangea often fails to bloom here in Chicago because the flower buds, formed in early fall, don’t survive the cold winter. “Don’t prune big-leaved hydrangea in winter, or you’ll cut off the flower buds and they won’t have any chance to bloom,” Janoski said. “We recommend pruning out dead branches and stems in early spring and leaving the rest of the bush intact.” Newer big-leaved hydrangea cultivars that are relatively hardy include Twist-n-Shout, BloomStruck and Let’s Dance Big Easy.