(Who's wondering how much more it would've cost to just paint some cornflakes white and have them strewn about.)
I thought I had read once that TV/Movie sets used Ivory snow or potato flakes to try to make winter scenes look real. Then again, you'd have to clean up the mess to make it look like summer again in the next scene.
And, I guess, not to mention having two types of trees: leafed and leafless. My favorite is when a winter scene, even a blizzard, is shot on an exterior set, and there amongst the huge drifts of snow are trees with their full bloom of foilage.
Little House On the Prairie was notorious for that. But then,
Dark Shadows '91 had palm trees sprouting in Collinsport, Maine. No wonder they always had such mild winters there.
Gerard