I like it, but before I can really offer critique I need to know what your end goal is:
If you want to make it look like a plant with brightly colored leaves,
Or, if you want to make it look like it's literally on fire.
You have some great shapes and colors laid down here, and I enjoy fires and such. (you have no idea. I made thermite in highschool, I had to steal FeO3 from the school's science cupboard... Actually a teacher knew I was in there. I just want to sound like a terrorist) But at any rate, I've figured out some nice methods for drawing flame that I can go into more detail about if you want to hear them. I have less advice on the plant front. You would have to ask someone else about those. Khalid_ipda has some great vegetation scenes, looking at his work could help, and coops has some really great flowers if you want to look at how other AR users did those =D
Early to bed early to rise makes a man stupid and blind in the eyes - Orson Scott Card