Hi Martin
Very good and easy to follow.
I've been making diorama type scenery for military and railroads for many years.
Would note that my preference is toward a darker earth and black wash undercoat colour which gives shadow depth around scenics and less eyesore when accidentally damaged. Scenicing for pleasuring the eye and convincing brain about what looks natural.
As for tufts, grasses and reeds in N scale, I'm happy with those tufted versions for manual placement. Same as you, spot of glue at desired spot, and lay down a blend of sizes and colours.
dave