Making Bushes/Shrubs

Take a look at the moss Shep Paine used on the Jadgpanzer IV diorama...  I'm not exactly sure what kind it is though.  He just says it's "garden moss"... 

http://www.itzproductions.com/Misc_Pages/shep_paine.htm

I've used lichen, torn into "branches" and then sprayed it with clear varnish, then dipped and rolled it around in dried oregnano, thyme, and dill as well (Gives the build an interesting smell, too)... Then spray it again to lock everything down.    I use tempra paint to mix up various shades of green and tan to spray it with.  It's a lot cheaper than using hobby paints and goes a long way.

I use white glue to fix the stuff to the model on the top, sides I use CA... Don't just glue it haphazardly all over the model though.  There needs to be a way that the crew made it stay there, so you should model that as well... Vehicles that are parked in position, like howitzers, SP guns, tanks in ambush, etc. you can lean branches against them, "moving" vehicles need straps, ropes, or wires holding the greenery in place...  For tall grass camo, like you'd see on the Russian Steppes, I use paintbrush bristles... A cheapo, 4-inch brush will give you enough "grass" for two or three models...

Try actual twigs or dried flowers for the scale you are doing. Spray with laquor hair spray and dip into colored sawdust or grind up actual dried leaves instead of the sawdust. Goldenrod when it dries makes a pretty believable small tree after applying the sawdust. Too lazy to color sawdust? Visit Woodland Scenics and buy ground foam.

WOW! you sure asked a lot there! I for one have used the woodlands vegitation on a 1/72 scale tig 2 tank. Looked fine to me! A branch here and a branch there. I also went for a walk in the bush and took a reall good look at some smaller twigs on small plants. However, I didn't really find much so that's why I went with the store bought stuff. If you have the patience try making a couple of twigs out of wire and spices from yer spice rack. Twist the wire and glue on the dried spices. Sounds goofy but it works mate! But seriously, don't sweat the small bush. I'm certain that whatever you end up with will be fine! About the color think about this: DON'T WORRY ABOUT IT. Most camo was done in haste and there was no set rule about color. As long as it wasn't bright pink or blue and blended into the surrounding vegitation it was fine!