Area I wish to cover:
The black polyfil I use
A wad of suitable size and mass
White glue and water bath
Black polyfil hydrated with glue/water
Squeezing glue/water out: not too much and not too little
Ready for top-coating
Some ground foams added
Rough placement
Edges tapped down, ground foams and some lichen added
AHA! Too much glue left in mat. Just pat it dry and cover with ground foams
Finished?
Tips: Sometimes I will stretch it out flat and sometimes I will hump it up. Sometimes I will overlap pieces, add lichen and anything else I can think of to make it look interesting - like green polyfil for vines. If I squeeze too much glue/water out and it won't tap down around the edges, some cheap hairspray will take care of that.
Total time to do this: about 45 minutes, stopping to take pics, etc. I would love to see if anyone can take this concept to a higher level. If you do, please let us all know with posts and pics, etc.
Here's a couple more close-up pics. Click on any given pic to enlarge. There should also be a magnifying glass in that larger pic to allow you to really zoom in. How do they compare with the very top pic?
I'll let it up to you to decide if this technique has merit on your layout...