Adding physics to particle and foliage?

So basically I want to make it possible to have snow/particle system buildup on foliage (such as trees, grass, rocks, etc) up to a certain point. I’ve attempted to add collision to the particle system and setting the collision parameter to “Stop” when colliding, but it just looks as if the ‘snow’ is just round white balls. Is there a way to create a material, or particle system that creates realistic, dynamic snow that can build onto the environment around, preferably foliage?

Btw, I didn’t know where else to put this, as I’m a noob with the engine.