They really stand out against the pure white background well, so I assume they are a selection maybe?
Really nicely taken, the colours are great. And the mask/selection is really well done.
The only potential issue with it being so perfectly cut out is that you get a floaty feel to the image.
Which is fine if that's what you're after, but if not, have a google for "adding a shadow in photoshop" for ideas on how to add a shadow which would ground the image. I know it's a trick I've used (you can also do something really similar to add reflections).