Grass and tree

Here is a wip project I am working on.

I tackled two major thing of my to learn list. Trees and grass. I want to have a man sitting under the tree (which has not been given materials) but my main concern is about realism does the tree modeling and grass look real?

No. It doesn’t look real.

The grass is too saturated and the tree needs a better material (Is that just a plain diffuse?).
I think the sky is detracting from the image. Get an HDR for your sky or at least download a sky image from