This is an interesting technique but it didn't score very well here... probably for several reasons.
First of all, I think it's always a bad idea to use an 'outtake' from one challenge as an entry in another. There are so many photos here every week that 'new' and 'fresh' are always a plus. When people stumble across this image, they will mumble under their breath about 'leftovers' as the punch a mediocre score and move on to the next image.
Contrary to your own comment, I don't think it fits a square crop very well. The negative space isn't playing any 'positive' role in the composition. I think it would make an excellent long vertical image though :)
I'm a sucker for negative space but feel this would score better if it was straighter (the foreground) and in black and white rather then the blue tone.
Not sure I care for the darkness of this. I wonder if this was inverted in post processing, since the centers of the flowers are lighter and the outer edges, and I don't recall seeing orchids colored that way naturally. If that's the case, I think that this would look much better un-inverted. If it's not the case, I think that less processing would work better.