Hi, Ron, and welcome to WC! and to the w/c forums.
There is a trick to grass, but it is a very easy trick: it's a brush called a 'rigger' or a 'liner.' A book by Jack Reid, titled something like "Let's Get Started" will tell you all about it, including how to use it. (An artist showed me one many, many years ago, when I marveled at his painting. Just one of those tricks of the trade, so easy when you know the secret.)
Please don't buy the fugitive (i.e., not lightfast) pigments Mr. Reid recommends -- but in all other ways, that's a really good w/c book for beginners like us.
P.S. If you want simple fields, btw, rather than a few long stems, a fan brush is helpful. Or, pinch a round brush at its base and use that as a fan.