Hello Alessio,
Two things stick out here, fill flash to eleminate the shadows & a darker background. The darker BG would have helped make your subject more pronounced. Also some saturation of your colors (stem) would have helped.
Usually I do not like objects floating in a picture’s composition without an anchor point; yours has an anchor point which is the stem; and in this case I would prefer to see it much weaker to give a floating feel to the nice shape you have captured.
The harsh light and shadow cast on the stem is taking attraction from the shape especially with non-contrasting color of the background, and the right bottom side is under lit.