Hi Steve, 

Based on our research, the Sta-Green weed & feed products are meant to control broadleaf weeds, so the native grasses should not be affected.  However, please carefully read the label of the specific product you plan to use, to be sure 1) it targets the weeds you want to control, and 2) it doesn't target any grasses.  Please read the instructions on how and when to use the product, and any safety considerations.  We are also providing you with the link to the National Pesticide Information Center http://www.npic.orst.edu/ in case you want more information about any of the pesticides you'll be using. 

I'm going to share some general information about lawn care, controlling weeds in a lawn, and ornamental grasses.  You may want to adjust some of your lawn care practices to help reduce weeds.  

Fact Sheet 7.232 Ornamental Grasses https://extension.colostate.edu/topic-areas/yard-garden/ornamental-grasses-7-232/

Fact Sheet 7.202 Lawn Care https://extension.colostate.edu/topic-areas/yard-garden/lawn-care-7-202/

Fact Sheet 3.101 Control of Annual Grassy Weeds in Lawns https://extension.colostate.edu/topic-areas/yard-garden/control-of-annual-grassy-weeds-in-lawns-3-101/

Happy Gardening! 

Trish G.