What would this ground cover be? Elfin Thyme? - Im looking for an appropriate ground cover for between Oklahoma flagstone on two patio areas...one will be a bar area where there will be bar stools and other dining area with chairs and table...concerned with legs of chairs sinking...is Elfin Thyme ok or do we have to use grass? Dining area gets some afternoon sun and bar area morning and little afternoon sun. Thank you for your help. »