I think the background plan is a little distracting & the composition of the plan creates odd triangular shapes. Maybe fade out the plan more so that the gray rectangle isn't so visible.
Also I think if you are going to have this sketchy watercolor look, you should do it to the entire image, & not neglect the trees.
I think the pure white poche & border could be improved. The ground shouldn't stop at the building, it should be below the building.