We have to fill the rest of the empty background, but for the beginning mark out and copy (ctrl+c) the upper part and insert it on a new layer (ctrl+v) that will be placed above:



Merge down these layers: Layer ? Merge Down (ctrl+e) and select the Stamp Tool of a big size to copy the grass on that place it was removed and fill the combined part:



Copy this layer (ctrl+j) and blur out the copy, using Filter ? Blur ? Gaussian Blur.



Create a mask out of this layer: Layer ? Add Layer Mask ? Hide All and then select the Gradient Tool of white color to make the blurred layer visible only on the backside.