Overall, I like the colors in this photo. The pinkish/purplish/red really contrasts nicely with the green. Also, your composition is very strong by having most of the cactus out of the frame, but having it "sit" in the bottom left. This positioning gives a feeling of strength and stability. I was going to comment that I felt a stronger, clearer focus would have helped the shot. But, I see below that you actually have a couple of comments about the good focus, so that is obviously just me, I guess. In my opinion, having the whole cactus in razor sharp focus (no pun) would help increase the contrast with the not focused background. The only other aesthetic thing I would change is the color of the background. It is kinda "dull" (in tone or mood, not interest level), and I think a brighter color would help it stand out more.
As far as the challenge goes, to me, this is almost just shallow depth of field. More of a pattern of color(s) in the background would have helped address this, I think. Perhaps if you had a couple other of these plants in the background, or something like that.
Overall, a fairly solid shot.
Good work and the best to you in future challenges.
yes, you have bokeh, but, for me, the way it is producing a split horizon takes away from what could be an excellent image. if you had changed perspective to have either the green or the tan as the whole background, this would have rocked. excellent focus, lighting, choice of colors, and dof, as well as an interesting subject. good luck!
If the things in your background were close they would have come in a little better as true bokeh, but the effect simply isnt there in this picture. Nice clear focus on your subject....but the background is missing information.