We're in El Paso, TX where it's usually pretty warm most of the year. We're coming up on some 20 degree overnight weather pretty soon and I wanted to know if there was anything I can do to help my fountain grass survive (just planted this June). Right now we have 2-4 inch river rocks around the bases, but can add mulch if needed. I've read several different suggestions and am not sure who to listen to. Thanks for any advice in advance, as my daughter tells me I have a black thumb!