The lack of responses clearly indicates we are stumped by your situation. Hahahahaha

You might want to try one of the groundcover roses. They are supposed to cascade well and would probably work better than vines, which tend to wrap themselves around every other plant they can reach!

Thank you audrey. I hadn't thought of carpet roses. Is there a good source online for those? I haven't found any locally.
Sorry to "stump" everyone. lol

I think most vines would get too large for this area... as most vines were "designed" to reach and reach for light. The only thing I can think of is petunias, but they are annuals in your zone.

How about a smaller sized grass? It may come out of the stump like a fountain! Grasses come in a wide variety of heights.

Good luck!
Susan