KEY problem is climate, specifically winter lows. But, with climate change, I’m now routinely fruiting some of the cold-hardiest muscadines in NW Arkansas. I don’t spray a thing. They are very vigorous, so be prepared to prune, as pruning is necessary to keep plants healthy and bearing.
IMPORTANT NOTE: We are pushing the envelope with muscadines. “Officially” (Cooperative Extension recommendations), they can’t be grown in NW Arkansas or colder than USDA Climate Zone 7a with a predicted low winter temperature of zero degrees F. However, we’ve been growing and fruiting muscadines for over 12 years now and have very little cold damage. Nevertheless, young, newly-planted vines are more tender than older plants, so we suggest mulching them heavily at planting. Also, it’s VERY common for new vines to die back if temperatures dip below zero for a short period but then the roots send up a new shoot. Accordingly, don’t give up if you think the vine has died–just be patient and keep the planting area weed-free.
Muscadine pollination is unique: plants are either self-fertile or female. Self-fertile varieties can be planted by themselves and still have fruit. Female varieties must have a self-fertile variety within 50 ft.