Hey mate,
Good on you for trying manual blending. If the sky in my histogram is blown, to ensure my foreground is exposed just how I wanted it, even when using graduated neutral density filters, I will take another shot of a correctly exposed sky, and blend it in using layer masks. There's no other way to capture such a huge dynamic range in those situations.
HDR (Photomatrix, etc) does not work. It renders images looking like cartoons, no matter what intensity it is applied at, with weird and wonderful saturation, contrast and shadow artifacts. Particularly around straight lines, you're left with unnatural halos. The algorithms try to guess what values a pixel gets rather than what they would have got in reality.
I think in this image, if you were to reverse the focus of contrast, it would really make the image pop. To explain what I mean, if you look at the flower itself, it looks like it is too smooth; it's lacking contrast. Compare that to the background, where you have deep rich blacks, your eye focuses more on those regions, where you want to showcase the jewel in the crown. I'd perhaps give the rose the same level of contrast as the background, and, then reduce the background's contrast by 2/3rds of a stop.
H