Brian - I sent the pix to Ron Rabideau formerly of Rarefind Nursery and had a response within milliseconds:
"Looks like Broussonetia papyrifera, Paper Mulberry. Nasty urban weed tree right in my back yard. Luckily mine don't fruit but I have seen fruits at Bartram's Garden. They turn orange. And sucker like mad. Ron"
In the early 70's there were huge ones lining one of the main historic streets in Williamsburg, Virginia, I admired their stunning bark. When we were back there around 1999 they were gone. Love the fruit and doubt they'd be weedy or even flower here. You'll have to get some seeds if you're back in time.
john