We have a poly woven type. Just spent 3 months in FL Grass was starting to grow up through it. They were made about 6 miles from where we stay and a lot of people in the park used them. I also have one of their sunshades.
You can call Beasley Mfg in Center Hill, FL on Tues-Wed-Thurs between 9am and 3pm at (352) 793-5055. They only operate from Nov 1-Apr 30.
Small local company. No web site they can probably mail a flyer with info. They make sunshades, grass mats and windshield covers. They don't take credit cards or debit cards either.
I have no affiliation other than using their products.