My neighbor (several houses away) has four mulberry trees and countless
little mulberry trees growing along the fences. I have a weeping
mulberry as well, but the berries are not nearly as good (or as big) as
hers. Briefly, this fall i would like to go there, relieve her of some
of the bigger weed mulberries, and plant them in my backyard. That
would save me several years over starting from cuttings (the biggest
ones are 8 ft tall and bushy). The weed mulberries are certainly the
descendant of the trees she has, I see no other mulberry nearby and the
birds swarm them in june and july.

Now, my question: of the four trees, two fruit profusely, one fruits
little, and the best looking tree nearly does not fruit at all. I
googled it, but I wonder if there is something I need to be aware of
when I select my future trees this fall. They are not male-female, so
is there anything else that affects fruit production.