Marta Matvienko, of ReallyGoodPlants.com has posted a Youtube video of her summer pruning technique to bring a vigorous 4 y.o. ‘Black Prince’ mulberry back into a manageable fruiting size/shape. It can be viewed here: https://www.youtube.com/watch?v=8yGgDyip7d8
I’m sure some folks would be shocked and taken aback by the wholesale reduction in size/height, but these are big woody weeds, and I’m sure that a well-established tree such as the one in the demonstration will respond with lots of regrowth of branches that will fruit next year.
Good share. Mulberries handle hard pruning like it’s nothing. I cut mine back aggressively mid-summer two years ago expecting it to sulk and it was throwing new growth out within two weeks. They fruit on new wood anyway so you’re not really losing next season’s crop.
So glad you posted that. I just pruned a dwarf mulbary tree a couple of days ago to reduce its height and develop more of an open center form. Afterwards I was concerned I’d pruned it at the wrong time, as it seemed to be bleeding sap afterwards. Glad you posted this as it reassures me that I was doing things correctly.