You don't say how you are growing them, John, so we can't tell if you are doing anything 'wrong'!
Both plants like cool, shady and moist conditions, even humid for the Shortia. I suspect that your main problem is your location and there is probably not much that you can do about that. Try giving them a humus rich soil in shade and keep them misted in the warmer, dry weather.

Most on here know that I don't like the use of peat in gardens. Shortia is one of the few plants that I would make an exception for. We have one plant in a pot of peat and grit sited on the north side of the greenhouse. Last year's wet summer suited it admirably but it is not so happy this year.

thanks bulbaholic for your help,shortia and paris are already growing in peat and have shade will certainly try spraying with some nice soft water