Can someone please tell me how to get rid of the blur on the middle?
That’s not blur. It’s a moiré pattern It’s caused by a combination of the closely spaced lines in your model and the pixels in the image. To get rid of it zoom in (although you may not be able to see the entire model, or get rid of the closely spaced lines.
The moiré effect might be lessened if you used a semitransparent PNG texture to mark your trellis instead of actually modelling it. It is also less prominent if you print or output your view to a higher resolution than that of your computer screen.