I think the frosted branch makes for an interesting subject and I think you were correct in using a wide aperture to blur the background. For me, the branch and tree trunk on the left detract from the composition. I'd crop out those out.
Also, I think the subject lends itself to black & white quite nicely. I took the liberty of converting it in Photoshop with an infrared filter, followed by 5% of Cooling Filter (LBB) and some minor tweaking of the curves and white and black points.
[attachment=22655:frost_mono.jpg]