Hardy panicle hydrangeas
Panicle (H. paniculata) hydrangeas are especially recommended for the Midwest because of their cold tolerance. Panicle hydrangeas bloom best in full sun, and most are hardy to Zone 3. Because of their larger size (6-8 feet tall and wide) and vase shape, panicle hydrangeas often appear in hedges, borders or as a garden's focal point.
"It's hard to beat a paniculata for the Midwest. They're just plain beautiful plants," says Tim Wood, horticulturist and product manager for Proven Winners ColorChoice plant company in Grand Haven, Michigan.