To me, it looks like there could be 2 grasses in this pic. The flowers belong to Paspalum dilatatum, or a similar Paspalum species, and the taller grass looks like Panicum virgatum.

Did you plant Gama Grass, Tripsacum dactyloides, or Grama Grass, Bouteloua curtipendula, gracilis? The flowers on your plant also look similar to Tripsacum dactyloides.

Tripsacum dactyloides

Paspalum dilatatum flower with pubescence.

Yep, Tripsacum dactyloides. I said Eastern Gamagrass. The photo is one big clump of grass where I planted one big clump of seeds. Other places where there were clumps of seeds look the same. All the grass in these clumps looks the same to me, with the exception of one or two stalks which are likely just volunteers. These flower buds in my picture have terminal inflorescence, as in your Tripsacum dactyloides picture. The Paspalum dilatatum buds in your picture look lateral. That's one reason I'm leaning towards Tripsacum dactyloides, which is what is supposed to be there. I'm assuming the buds haven't yet quite opened into flowers, which is why I don't see the orange flowers in your Tripsacum dactyloides picture. Assuming I eventually see those flowers, I'll be more confident. I believe that's supposed to happen in June. Is this, in my picture, what the seed head of Tripsacum dactyloides is supposed to look like, before it blooms?

Yes, the Tripsacum flowers are still forming. I thought there were 2 different grasses when I thought your plant might be Paspalum, who's leaves look much different than Tripsacum.

Very good. Thank you. After the gamagrass was killed to the ground, I didn't know what was going to come up to replace it. Lots of random wild grasses growing down there. The gamagrass roots were well established by then, so I guess they did the job. This is wonderful stuff. I'm told by my urban creek experts that gamagrass is great to plant in the creek because in high water, it just flops over and gets out of the way. Also, the roots are very deep, so it's excellent for bank stabilization and is highly flood-tolerant. It's also native and not very invasive. Not very cold tolerant I guess but, somewhat oddly, it requires stratification to germinate. It is related to corn so, if desired, fertilize as you would corn. That means nitrogen.