Beginner Gardening: Need Help Identifying an existing ground cover, 1 by kjuddy

kjuddy wrote:
I am helping my boss with a landscaping project and need a little assistance. He has a very formal landscape that was put in before he bought his house probably 10 years ago or longer. Lots of boxwoods in groups of three that line a very long pathway to the house. Hot afternoon sun. Underneath a crepe myrtle behind the boxwoods and around some other bushes is what he describes as a non-blooming ground cover that has been very hard to remove. He pulled up one of the plants and brought it to me and it looks very much like a daylily plant - tuberous roots with a sword shaped fan on top of them. They don't appear to clump like daylilies but other than that the plant itself is very similiar. I would like to identify the plant so I'll know whether I want to keep some or dispose of it all. Here's the best shot of it he brought me the left side is lirope and the ground cover is the small very green stuff coming up to the left. Thanks for your help.