I have several of these as well as the "regular" jacks. I don't do anything for them. My soil is rather acidic, and the plants are in wooded areas...no sun to speak of, just reflected or dappled shade and some heavy shade.

No one around here has mentioned any difficulty in growing these plants. Maybe your area is too hot?

I mostly find them along flood plains in the wild, so I would guess moist, fertile soil would be preferred. They grow in calcareous soils around here.