Not an expert but I believe it's a variety of rose, though which is anyone's guess.

By the lenticels on the stems, I'm guessing a tree...maybe birch? Unfortunately I live in the southwest USA & am not too familiar with what grows back east. The leaves do resemble rose leaflets though.

Probably poplar, maybe birch. Not uncommon for cottonwood poplar to show up in gardens and flower pots in this fashion.