I would have increased the DOF such that it pulled the center portion of the flower into focus as well and also, because you have some decent horizontal symmetry going, I might have tried a square crop with the flower dead center in the frame or a portrait orientation. Nice control of the reds which have a tendency to blow out.
The background blur works nicely in most areas but there are a few that are radically blown out that cover some distracting real-estate. The out of focus areas such as the stem and whatnot give a nice context, though.