I installed a vertical barrier 3 or 4 years ago. So far, no escapees. However, I installed mine before I planted the raspberries so you may have more issues installing and containing growth that is already outside of your patch. My patch is tiny, so I dug down manually with a trenching shovel.

I used 20" aluminum roof flashing. Sorry, I don't know if 12" is enough. I have just a tiny bit of the flashing showing above ground level. It shows no signs of deterioration.

It sounds like the aluminum flashing would be OK and maybe I need to step up to the 20" size. I will probably trench this in on both sides of the Boyne. On the other side (opposite the blueberries) is a row of Autumn Britten Raspberries. The Boyne are trying to invaded them as well.

It will be easy for me to isolate Round-Up spray on the Boyne suckers in the Blueberry row after their connecting roots have been severed. If I do it now, it also kills the parent Boyne plant that it is still connected to. Found this out the hard way.

cut primocanes flush with the ground around the first week of May. Tip primocanes as they grow to promote more laterals and time plants to flower when you want to harvest in the fall. Approximately 30 days from flower to fruit. Sept 22 is the fall equinox and should naturally trigger razz plants to flower. 12/12 light dark cycle

Installing vertical barrier seems like a lot of work. I would remove the weed barrier tarp so that the runners don't go al the way over to the blueberry plants and then just clip them off with a shovel as they come up. I have my raspberries about 4' apart and runners come up through the bark walkway and I just hit em with the shovel once a week, very easy, takes just a few seconds. Mid way through the growing season the runners stop and it's no longer necessary.

RM

Yeah, they pull up easy when young. Stick a few in some small pots and give some raspberries to your friends!