I looks like nutsedge. If you only have one of them, you are indeed lucky. If it is nutsedge, DON'T pull it whatever you do or there will be 4-5 times that many in a few weeks. Carefully dig it out, making sure to get a good amount of the rootball. Make sure you dispose of the plant.

Here is a link that might be useful: Nutsedge

Thank you for your response. Good thing I didn't pull it out. I was just thinking that it was looking almost 'legitimate' that I thought I'd ask first.

I don't think this is a nutgrass. For one, the growth habit just isn't right. It also looks larger to me...how tall is it? And I've never had nutgrass give me a cut.

If you hadn't mentioned getting something akin to a 'paper cut' when you touched it, I'd say it looks very similar to my 'Green Giant' lily turf - except not as lush. It isn't nutsedge....that stuff is the bane of my existence, and I know it when I see it.

Seeing as how it's nearly 3am here, and I don't have a picture of my gg lily turf handy which I could post, I snagged a couple off the web for you to look at.

giant green lily turf (aka evergreen giant liriope, among others)
{{gwi:1350523}}

{{gwi:1350524}}

Does it look like it could be your mystery plant?

Well, I googled 'sedges', and I have to admit that your plant could be another type of sedge. I'm still positive it isn't nutsedge, but maybe umbrella sedge, or flat sedge. Some of them are sold as water/bog garden plants, I noticed. So it could still be a keeper.

Sorry for the lack of response!

I'd say it's about three feet tall and that's including the leaves.

Rivers, The pictures you provided doesn't match the mystery plant. It's way too leafy and doesn't seem to have any stalks that support another set of leaves at the top.

Here are the latest pictures, I'm sorry about the quality of the pictures. Apparently too much sun can also affect the pictures.