I don't really know but could it be too dry? Do the buds shrivel up before they open. Or is it too light, I think they might not like too much sun.

Gardenias like more sun than most realize. Is it in a pot, Gerald? They don't need watering that often, but wilting can easily kill all the buds. Lack of acid in the soil can kill the buds, also, so I would definitely use an acid-forming plant food.