I may have planted this. My husband wants to whack it down. I’m an ignorant but loyal botanist.
your plant is one of the wild blackberries, maybe Rubus allegheniensis. They are very difficult to separate into species without flowers or fruits. They are native, and they can be weedy – it just depends on whether it is worth it to get a few berries as time goes on, I guess. Certainly the fruits would be edible.
Dr. Steven Hill, Botanist, SCNPS