If I were to plant those, I'd think about ease of harvesting and put up a fence for them first. I'd want to be able to train/tie it to something to keep most of those thorns out of me.
I'd also site them carefully; for most of the year they might be a hindrance if they were near a heavily-traveled walkway or an outdoor gathering area.
In order for them to quickly become self-sufficient in your yard, I'd suggest mixing compost with native soil (from the planting hole), about 50/50. Plant and back-fill, then slowly add water until the area is soggy, top it off with dry native soil, then pretty much leave them be until they settle in. Once summer comes around, if there's low or no rainfall give 'em a good, slow drink so the water goes deep -maybe once every two weeks. A top-dressing of compost might be all the food they require, but on that point I'm inexperienced since all of our fruiting brambles were inherited with the property and are growing wild and willy-nilly amid the weed willows along the lakeshore.
It's pretty tough to harvest those without getting ripped to shreds.
Hopefully, someone will be along soon to address the feeding schedule, if any is required.
