I wasn't sure if this "stem" in our yard was alive or dead. Well, I guess it's alive, as it's sprouted leaves. It's still only about 2 feet high, so I don't know what exactly it is. I originally thought it was a rose bush, but it doesn't have thorns.
It might be a volunteer. It may be too young to bloom this year, and that's usually the easiest way to ID things. Keep an eye out for that foliage on a larger bush/tree in the neighborhood.
