Possibly nutsedge? I have some coming in now on Long Island.

Looks like nutsedge. Ortho Nutsedge Killer or another sulfentrazone based product will kill it. Test it on a corner of your lawn and give it 3-4 days to make sure it's safe for your grass before your blanket spray.

I haven't seen any flowers or anything when I let this stuff get long but I'll try the nutsedge stuff. Where would this stuff have come from? There has not been any grass growing in 15' radius's around these trees for the last ten years I'd say. And this 'weed' is only growing where there was no grass previously, there is none of it outside the newly planted zone in the established grass. Just a little confused, thank you all for your help!

Can you post a closer picture of the offender in your lawn, it might be orchardgrass that came in with your seed as weed seed.

I will tonight when I get back home, you want a closeup of a few blades where they meet the ground or what would you like to see? Thanks again for the help!

Just take a picture from 2-3 inches away of a clump of the weed where the blades are clearly visible.

Orchard grass would get seed heads. So would crabgrass. Nutgrass is usually darker green.

Where do you live? It's hard to guess what kind of grass you have, but knowing where you live helps to eliminate some possibilities. Does the offending grass have a pointed tip or rounded?

Nutsedge probably wouldn't get enough water that close to a tree, but anything is possible. I was thinking Poa triv

I live in Minnesota. Hard to say on top shape as I just cut it but I would say it's more pointed than it is rounded when long. Here's a few more pics.

Thanks again you guys for taking the time to help!

I'm going to stick with orchardgrass. It's a common contaminant of seed mixtures and it falls under "other crop seed", not "weed seed". Nutsedge has more prominent center ribbing. It's also not as wide and more glossy.

Agree with j4c11.

Ok, thanks guys, so what's my best course of action?

There is no selective herbicide available for orchard grass, sorry. Roundup is the only option. You could take a paintbrush and paint some only on the weeds to save the grass, but that looks like a lot of work.