This looks tough, but it's actually really easy. Here I've found myself against a tree with seemingly no way to hit toward the flag. What's the solution? I've turned my back to the target and am hitting it backward. I've chosen to use my sand wedge, so I can stand close to the ball and hold it at a length that I feel gives me control. The big key is to rehearse impact a couple of times, much like a pool player rehearses prior to his shot. Once I feel like I've got it, I swing away.
Hold the club at a length that gives you control. Then rehearse your impact position a few times.