Stunning light on these delicate blooms. Personally, I would crop some of the negative space on either side of the cluster, as well as the two small points of green at the bottom, to me they are a bit distracting. I've always been a fan of plain black backgrounds for flowers, so I'm not bothered by your choice, just my personal preference. Overall, a beautiful image!
I am very interested in Helder's comment. I personally like this image very much and think the contrast is perfect! I hope Helder explains more for my knowledge.