Light tan mixed with dead dull grass and with some lightly sprayed blacks in the background to add depth and shadowing. If you want it to look really nice you can buy the stencils from the various sites or create your own. I always made mine by going to the dollar store and buying the Teflon cookie sheets. Found a patter of the internet that I liked, printed it and laid the clear Teflon cookie sheet over it and cut it out with an exacto. Easier to buy, but around $50 dollars. I just enjoyed the entire process, so that is why I did it. Did an aqua pod using an enlarged DU shape. I did the base layer with darker brown, so the pod was covered with DU signs, then went over with olive drab, then the tan. Looked pretty good when finished.
Another pattern enhancer is using ferns as a stencil. The finish work blends very well given all the fingers. I usually held the can away from the boat, so all the colors were soft transitions for better blending and not hard lines.