It has been grown widely from the Indian subcontinent west through Afghanistan and Iran to southern Europe for over a thousand years for leaves to feed silkworms. More recently, it has become widely naturalized in disturbed areas such as roadsides and the edges of tree lots, along with urban areas in much of North America, where it hybridizes readily with the locally native red mulberry "(Morus rubra)". There is now serious concern for the long-term genetic viability of the red mulberry because of extensive hybridization in some areas.