Maple Leaf is an alba and typically they are very cold hardy but I don’t think Maple Leaf is. It buds out “very early” and wouldn’t work in z5 but might in z6
From another thread
Sorry @rubus_chief …I haven’t received any feedback as to its cold hardiness, but I feel that it probably can’t take a zone 5 winter since it buds out very early in the spring. Bass Samaan (of Facebook’s Mulberry Growers) might be able to provide some insight since I believe that he named the cultivar (but I could be mistaken). Let us know if you get any info on it.
You should be good with any Rubra hybrid and might look at Silk Hope (some prefer over IE) or Kip Parker (again some prefer over IE)
Oscar is another to look at