I have an article in the March 2005 Railroad Model Craftsman showing how to make model grass using dyed faux fur. It is centered on dead grass for California modeling but also demostrates green grass, bushes and brush. The original web article is at:
http://www.pacificcoastairlinerr.com/fur_grass/
I am amazed at the outcome of this process and hope it is helpful to your modeling.
Faux fur high grass and low grass on the hill with an On30 Bachmann Mogul
An HO figure with faux fur low grass
Squeaking my wheel & Blowing my horn
Haroldhttp://www.pacificcoastairlinerr.com/fur_grass/ho_balsa.JPG
http://www.pacificcoastairlinerr.com/fur_grass/
I am amazed at the outcome of this process and hope it is helpful to your modeling.

Faux fur high grass and low grass on the hill with an On30 Bachmann Mogul
An HO figure with faux fur low grass
Squeaking my wheel & Blowing my horn

Haroldhttp://www.pacificcoastairlinerr.com/fur_grass/ho_balsa.JPG