My blackberries are in rows with two strands of hi-tensile wire running down the rows, lowest one about 2 feet from the ground, highest about 4 1/2 feet. I kinda wrap the canes around the lower wire and tie them to the top. You can't let a first year cane touch the ground or it will start roots for a new plant and you don't get any berries from that cane, so it's pretty important to keep them tied. I also prune the tall canes back some in late spring to encourage more berries. I set the rows far enough apart that I can run a bush hog between them to keep weeds down, then use a gas trimmer to clean up between the plants. I get about a gallon of large berries from each mature (3 year old) plants, right now I've got about 36 mature plants. It's not hard to find people that don't mind picking blackberries from thornless plants, everybody on my side of the family and my wife's side tear them up.
I have started another patch, letting the canes start new plants to be replanted back into the rows so that in a year or so I can sell some. Around here, U pick blackberries on thornless canes go for $8 a gallon! That'd be an easy way to make an extra 300 or 400 dollars during the summer and they don't take a lot of care. Just keeping them tied up, a little pruning, cutting out the old canes and running a bush hog down the sides.
We make a lot of blackberry and strawberry jam and there ain't much better than some biscuits and homemade jam on a wintery day or a good hot blackberry cobbler!
