This is absolutely beautiful.
I like the roundness of the orb. I will agree the rest of the piece doesn't match it enough, but I would rather you changed the rest of the piece, honestly.
A few more cracks or grass on the orb could be nice, but it is quite amazing already.
Here is what I mean by change the rest of the piece:

I made the clouds seem to circulate around the orb. Same goes for the shape of the tree.
For your leaves I noticed that your grass is pretty sharp, so I made them sharp as well.
Hope that's what you were asking for and that it actually helps you out.