My Morus Nigra--Noir de Spain is four years old now and about 15 feet high, and this year I've got a nice big crop, and they have begun to ripen.
I also discovered some mulberries growing in our local park, and sampled some and--what a difference! They have an immediate mulberry flavor, which dissipates quickly into insipid. (I think they are white mulberries, but who knows, the tree trunks are at least six feet across so they are probably a hundred years old)
MY mulberries are absolutely delicious, heaven, like the most flavorful sweet/tart blackberry there is. It must be the difference between Morus Nigra and Morus Alba. Glad I planted the right one!
Carla in Sac