Are St. Augustine and fescue grasses suitable lawn grasses for zones 5a/5b, northern Illinois. If not what is recommended?
Certified GKH Gardening Expert
St. Augustine grass will not likely survive well in your area. Fescue will be barely hardy in your area. These grasses are too warm natured, and too cold natured, respectively.
This article will give you some better suited grasses for your area: https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-5/zone-5-native-grasses.htm