I'm in z 8a (SC midlands), and I'm trying to figure out my yard's microclimates, but it's confusing.

For example, my sagos can survive without protection but turn 95% brown, but some sweet potato vines that I leave in the ground come back the next year. My ginger lilies and papyrus and dahlias do fine without protection, but my cannas get stunted if I don't dig them up. I tried to protect a few of those commonly found variegated red bananas, but none survived. Even the musa bajoo doesn't do too well for me. It survives, but dies back to ground completely and never grows to more than 3-4 feet. Spanish moss does well for me, surprisingly, but not for my friend 5 min away, but her sagos don't turn brown, and her musa bajoo's are enormous. Some of my fatsias die down almost completely (but grow back), others make it through winter without any problems. And they stand only a few feet away from each other.

My yard is exposed to a lot of wind coming off a lake. I thought the water would have a moderating effect, but it seems to be the opposite. Any advice? Could the plants be drying out more than being cold? Or is it the wind chill factor more important than the actual temperature?