Hi James...
The base growies are static grass... It's a mix I put together ages ago by combining everything I had into one big box...
Once the grass is dry I lightly brush some of the clumps with PVA and then sprinkle ...heavily with K and M medium olive flock...
The effect I am aiming for small leafed foliage like clover and similar plants...
I hope that makes sense and is of some help
All the best. Aly