I hear that most kinds of berries need trellises like the one pictured below. I believe that the trellis keeps the stalks growing upright. Beyond the aesthetics, would anything bad happen if I grew berries without a trellis - just let them grow to whichever direction that they want? I'm just growing blackberries and blueberries for the taste and don't really care about the appearance of the bush.
I've never trellised my berries, personally. I've thought of doing it, but never quite get around to it. If you don't trellis blackberries and raspberries, they kind of sprawl all over and spread to make a thicket in whatever area you are willing to give them. It can make it more difficult (and painful) to pick, but isn't a problem otherwise. I just put on long pants and long sleeves to pick.
