We recently purchased 15 acres in North Texas (Dallas area) and while I recognize most of the plants, there is one that isn't exactly clear. Initially, it looked like wild blackberry bushes, but the berries are too small. It might be wild blueberries, but it could also be some poisonous plant I haven't thought of yet. The bushes are about 3 feet tall and have not-quite-ripe berries, some times in clumps. The bushes seem invasive and are taking over several acres. It has very oval shaped leaves. Photo attached. I know the photo looks like it was taken with a calculator. I'll try to get better ones next time I'm out there if no one recognizes it.
Thanks in advance for your help!