Pine trees are usually self-mulching.

If you want a groundcover, how about pachysandra? It does well under pine and it also will grow to the edge of the driveway and street, eliminating weeds. It recovers quickly from any salt damage. Deer don't touch it. You don't have to remove leaves. I don't know where you are located, but I've been told that a pachysandra blight carried by boxwood is about to decimate this old standby. I can't even imagine what that will do to old NY suburbs like mine. Like losing the elm..

Yes, these pine trees are self-mulching, however, in about two weeks, the area below them will be covered in weeds.

You need to deal with weeds separately. Just planting groundcover does not eliminate weeds and the two mixed together look bad. Once groundcover becomes established it may keep future weeds out or to an absolute minimum.

Before planting a groundcover, create a clean bed by making it a perfect quarter circle around the tree. Don't accept the happenstance shape that occurs on its own (such as in first photo.)

Pachysandra seems like a good choice. Lily of the valley could be good, but it is not evergreen. There are other shade tolerant groundcovers for zone 5 you can Google. I would not plant shrubs (like Hydrangea.) It it much more effort to maintain and is likely to be too tall right off the bat.