Fun! Ok, I would make the petals a blue, like morning glory blue, merging into a blue/purple in the middle with black stamens (or small dots- hard to tell if there are designated stamen in the middle). The the hummingbird a ruby throated hummingbird to bring in some red pop. Below the flower, make the leaves a brighter green, not too bright, just more so than the current color. The flowers on the trunk could be variation of the purple and blue mixed together for highlights.
