Barberry. This is one of a number of evergreen barberry species. If you want a hedge that is impenetrable, then this is the ideal plant with its dense habit and prickly thorns. It can reach a height of 5-6' and lends itself to shearing. It is native to southwestern China and is one of those though-as-nails plants that takes little to no care and is very disease and insect resistant. It has masses of fragrant yellow flowers in spring which quickly followed by its brilliant glossy burgundy-red new growth which is a bright, and in itself is quite showy. We have had no deer even attempt a nibble on this plant.
Zones 5-8