The vase is crooked. Good white balance. Top petals on the flower on the left are a bit pinkish. There seems to be a strange reddish reflection in the bottom left part of the vase.
Lovely image, focus good, nice color, and well lit but the lighitng seems to come predominantly from the side. I can't see this as an effective use of backlighting. Really a nice photo though shows the talent of the photographer.
This is a nice, clean, simple shot - well focused; but I do not consider this to be backlighting. It also appears the vase is leaning a bit. You might consider rotating the shot just a bit counterclockwise.
If you have a black background then I think you should be certain to keep light off it to ensure it remains completely black. This can easily be fixed using "levels" in PS. Nice image though, just needs a little helping hand in post processing.