The brightest colour on the grass seems out of place (this is mostly noticeable with 2x or higher zoom); the second brightest colour is quite a yellowy-green, but the brightest colour is pure, hyper-saturated green. I think it would looks better with a more consistent hue ramp, so the colours are more yellow as they get lighter.
Oh, and probably lower the saturation of the palette in general a little, particularly on the darker colours.
Here's my try at a palette change:



