The flower is great -- both the flower itself and the leaves are nicely depicted. Agree that the strong vertical line in background is a bit distracting being right behind the plant.
I love the great contrast in the petals and bottom leaves. The darkness makes it look mysterious. I don't like the highlight in the background going straight up behind the plant though as it makes the composition static or something. I think if there were something vertical or diagonal to break things up it would have helped this composition.