Chapman,
Most Morus Rubra ( our only mulberry native to U.S.) are normally pretty tasty so don't sell them short. They will be nothing the size of the photos here. Morus Alba is naturalized here, but not native, and is more variable, from very bland to very good. You can't always trust the labels either at my local Pikes nursery they had plant labeled as "Native Mulberry" and the tag also stated Morus Nigra. If I knew for sure it was Nigra I might have went for it, but still dormant and not for sure I could ID even if it was leafed I passed. I don't believe "Native Mulberry" is a cultivar of Nigra, and Nigra isn't native to U.S. A seedling may turn out male however, as in no fruit:(