I remember telling my students to let objects touch, actually flow beyond the space on three sides of the composition to create interesting negative areas in a painting or drawing. I had that happen here, but I guess with all the color and shape going on, the negative space is about the last thing you see here, ha !
Color Note: I've noticed that when I've used ready-made greens most of them seem so transluscent and really not very effective. I went back to Carol Marine's list of colors (she has a pretty limited palette, I would say) and experimented with just her few possible green mixtures. She uses only Phthalo Blue and Ultramarine, along with Cadmium Yellow Light. I was able to mix wonderful greens from these two sets of combinations and they were much more opaque ! I also took straight Ultramarine and straight Phthalo Blue and mixed them each with white to really be able to remember the distinction between them for the future. (The circle on the left is the Ultramarine Blue)
On the green mixtures, the one on the left contains the Phthalo Blue and the other is the Ultramarine...