I don’t know if anyone has done a controlled study, but I don’t think it’s at all necessary. I’ve got autumn olives grown from cuttings, and they are growing great. As always, I’m interested in opposing views and different experiences.
They do bloom too early and always get frosted. I need to plant some where they have some shade and don’t bloom so early. My goumis bloomed later, so I
should get a few.