The Hardiest of Hardy Perennials. Generally speaking, a plant is classified as a perennial if it can survive to Zone 7. Above that range, plants become tender perennials or annuals. For the purpose of this article, we will only consider the "hardiest" of hardy perennials, plants that are hardy to Zones 4 and lower (or higher in latitude). The plants on this list are definitely tough enough to survive your area's worst winters.
I keep seeing the most amazing photos of this type of hedge and I finally learned the name. Miscanthus produces showy copper colored flower plumes in September and brilliant fall gold foliage. This perennial is zone 5 hardy and is both deer resistant and drought proof once established. Make sure to shear back this hedge plant in the spring to about 12” from the ground. This helps to re-energize the plant for the coming season.