This lovely photo by mettem at morguefile is used as the background. The only change to it, is that the fence was darkened as I went along so that the snow on the thistles would show up against it better.
Here the thistle source is moved over the horse background.
step 3 of 8
Thistles are chopped and duplicated, some rotated a little (edit/transform/rotate) and some are flipped horizontally (edit/transform/rotate) and moved until the pattern is satisfactory.
step 4 of 8
Beginning of snow is airbrushed over thistles at 'dissolve' mode at 33%
step 5 of 8
More snow is airbrushed in white and blue at 'normal' setting at 33% pressure
step 6 of 8
More work is done with paint brush w more pressure in blue and white to create some snow 'textures'.
step 7 of 8
Snow is now finished on thistles.
step 8 of 8
Finally a new layer of snow overlay is added at a large setting and with motion blur added.