Around here, blackberry bushes run rampant. They're everywhere that's even remotely neglected: a little patch of grass next to the train tracks, and certainly all over the woods (which, despite this being the Netherlands, there are actually lots of, just in patches).
They've got a little ways to go, about three more weeks, before the berries will be ready for the picking. I've got my bucket already.
For those of us into natural food, or free food, it really doesn't get any better than this. Just walk into the woods with a bucket, and a few hours later, you've got enough jam to last you until the next season. Spring for a little winemaker's yeast, and you can easily pick enough to make enough wine to sip over Christmas.
The one thing you do want to be aware of when you're picking your own produce from the wild is where you're picking from. The side of the road? Probably not so hot. And certainly, by all means, stay as far away from golf courses as you can get. You want to step around places that are heavily treated with pesticides and herbicides, or exposed to industrial waste.
It used to be that foraging for good eats was our main source of food. These days, we're lucky enough to be able to go to stores and pick out what we want. It always surprises me that, whenever I do go out berry-picking, I never see anybody else picking them--given what blackberries cost and the notorious Dutch stinginess (which I've yet to encounter), surprises me. It makes me wonder how it is that we're so far divorced from what real food looks like that we can't recognize it when it's growing in front of us.