Hard to make a guess based on your description. When you are able to post photos, I suggest you try them on the "Name That Plant" forum. Be sure to get photos of leaves as well as seed heads.

Might advise your mother to be cautious in making a lot of changes 'til maybe late spring next year. There may be bulbs and/or other fully dormant plants that are not obvious at this point. I, too, moved onto a property one November. There were a few scraggly flower beds. Next spring I was delighted to find several nice clumps of daffodils and some nice bleeding hearts (Dicentra).