Do you want to remove 100% of the background?... If so, the simplest method, in view of the colours involved, would be to use the "magic eraser" very tightly controlled, but with "contiguous" unchecked... for safety's sake, make a copy of the layer, then "hide" it.. click visible OFF in layers. probably set tolerance to about 50%, and do the blue first... when you do the white, make SURE there isn't any red tint where you click.... either that, or reset tolerance to about 5%... . One thing you might do, I find this helps me out, is to create a new layer... fill colour set at white, and move it "below" the layer you're working on.. otherwise, it gets hard to see. to change the colour of the "branches", you can use "replace colour" Lou.

"..... and that was when things got interestiing."