Wonderful sharpness and colours, I like the composition. Terrific quality I can appreciate the texture of the tulips. Maybe you guys can show the Dutch folks a thing or two eh?!!
You may want to consider lens correction if you haven't already, there appears to be a slight curve to the horizon (unless it is an optical illusion created by the reds an greens)
Nice composition, like the low angle and the flowers look nice in the overcast light. This looks more like a landscape then a macro shot to me. None the less still a nice shot.