Ranger is more associated with green than brown. Ranger is a bit more accounted with green as it's mainly shown as being the nature guardian and would be the one you'd actually see in mildly camo style greens. The Druid is more the voice behind nature that's well rooted in the earth and would have a lot less emphasis on colored cloths as blending in isn't their thing.
http://www.behindthevoiceactors.com/_img/chars/dandelion-the-witcher-3-wild-hunt-1.73.jpg