I think the pop of blue looks fabulous. If you are not confident with colour why not just leave Benj in colour and the rest in black and white. It would be a perfect shot for selective colouring.
If you want to direct our eyes to the main subject then this is one very effective way. I'm not too good at it but I usually say that I don't like it. My problem is removing distracting/unwanted colour without losing some other important feature. The selective colour in this shot has worked so well in focussing my attention on Benj that I don't naturally look for much else (because it is harder work), which is a shame because the trees are lovely.
