Whoever said that this is temperature-zone dependent: +1.
Don't overlook Jerusalem Artichoke, more a tuberous plant than a shrub, but once established they are self-renewing and the tubers pretty much substitute for white potatoes.
A wild cherry tree is a source of fruit in some ares and parts of the tree, such as the bark, are medicinal. The slick-barked part of a willow is basically natural aspirin. A poke root poultice, according to Mom, would cure anything but a broken heart. Ginseng has many uses if it will grow in your area.
Wild persimmon trees have goodly amounts of fruit and are a source of raccoons and possums for meat. Any nut tree that grow and produce in your area. Pecans are especially prolific in my area but take a long time to mature.