Make a dot with the 45 pixel soft round brush tip but use it in pencil mode. Make a bunch of other dots so indicate trees. Oh and use white. Fill the rest of the layer with black. Crystallize it at 12. Hit it with spatter, then hit it with glass. Delete the black and the rest is layer styles: color, pattern, bevel, glows, etc. For the branches, create a new layer and fill it with the default pattern metal landscape, then hit ctrl+i to invert it and delete the blacks...leaving white branches. Erase around the trees and then color overlay it with brown. For the blossoms fill a new layer with 400% noise, double the scale, blur, delete the blacks, delete the stuff not on trees, then color overlay.
Now keep in mind that this is PS so I don't know how well it works with Gimp or PSP or Paint.