I think you did a good job in use a narrow DOF, isolating you subject and making it stand out. By looking at you setting I can see that you were shooting in low light, wich has caused some noise on your background, I would also have prefered a smother transition between the two colors. Sometimes it's better to wait for a better light condition, so you can use a lower ISO and a faster shutter wich will allow you to get a sharper image.
Now about the composition, I think is pleasing, but it might work better if you fill the frame a bit more with your subject and moving it a little bit more to one of the sides, instead of entering the frame exactly by the corner.
Comment only: I would suspect this is scoring in the high 5s at a minimum but I'm lousy at estimating scores. In my opinion, this is a very good interpretation of the challenge. Some may want an even narrower DOF, but that's all a matter of taste/opinion. I particularly like the bokeh and the way it changes from lavender to green. I like the composition as well - works for me. If it's not scoring as high as you'd like, it may be due to the "flower factor" - there are probably tons of flowers and plants in this challenge, and to score really high with one, it has to be very dramatic and extremely well done. This is a very nice quiet shot - soft (in feel, not focus on your subject) and gentle. Nothing wrong with that at all, but sometimes that won't score as high here. Hope this helps!