Burnt Ridge Nursery has some good mulberry rootstock… russian mulberry… very cold hardy, very nice stout roots.
Late spring this year I caught them on sale 5.00 per rootstock.
I had good luck grafting mulberry scionwood to them. Kip Parker and Lawson Dawson.
Those are all planted out in my orchard now, and one at my daughters home.
I tried rooting gerardi mulberry and all failed.
I have had very high success rate grafting mulberry.
Those are the BRN russian mulberry rootstock above.
TNHunter