the grass you see above is woodlands scenics long grass.  It comes as a pack of bristles about 4 inches long and you cut it down and "plant" it in tufts.  It's essentially like someone cut all the bristles off a big paintbrush and put them in a packet.

I figured a good way to grass a large area was to lay a base of static grass down and then plant the woodlands scenic stuff down in between.  The static grass actually holds it up.  It takes a while but the results are nice.

cheers

Jon