I think I know what it is, but just need confirmation. It's been spreading for the past 2-3 years since we cleared around our home. Oh boy does it want to grow, too!

Sorry, I'm no help but we have the same stuff here.

That there is a Cherokee Sex Weed.

The taller ones are just after where I stop mowing, boardering the woods.

This past summer there was an area (one of the ones in my photos) where the stuff grew over 7ft in less than 2 months. It was crazy.

Looks like cat grass

White Tridens

Getting close. It is a native grass.

No sense it letting it draw out. It is only grass, lol.

I'm pretty sure it is Big Bluestem. It doesn't have the characteristic "turkey's foot" on the seed heads because they have already dropped their seed so it tends to collapse and look a tad wilty in winter. All the rest of the description of it seems to match what I'm looking at. The stems and leaves are still green, but a few are starting to turn a purplish blue and could turn red as well.

That bunch I mowed down this summer was a bear. I couldn't run the entire mower over it at once or it would immediately kill it, it was so thick and tough. But I'm still thinking about letting it run in an area where I have severe erosion. It hasn't made it on that side of my place, though, so I may have to plant a bit in that area.

So there it is, Big Bluestem.