Improved Chickasaw plums do very well here provided they are low enough chill. Good Chickasaw plums are much harder to find in the nursery trade than European and Asian plums. The reason is that while they are just as sweet and actually juicier than their Asian and European cousins, they are also softer and have a much shorter shelf life once picked. Consequently the commercial fruit industry isn’t interested. For some reason the big wholesale nurseries haven’t fully grasp the fact that while Chickasaw plums are not a good choice for a commercial farmer, they are a great choice for a home grower, especially if they are in a hot, humid climate with high disease pressure. Mariana is also a good choice if you have an effective pollen partner like Prunus umbelatta to go with it.
As for sub tropical fruit. A hand full of citrus varieties such as satsumas do well here as do Fajoia (Pineapple guava). We are not quite warm enough for most citrus and most quavas. God bless.
Marcus