Last year I planted two Frost Proof Gardenias. I am in NC zone 7b. They are planted as foundation plants and are east facing. They get plenty of sun, they have been fertilized with Hollytone (for acid loving plants). I have also applied compost, peat moss, epsom salt and coffee grounds at different times between the Spring and Summer. They are mulched with a thick layer of pine straw. The plants have bloomed however I get yellow leaves which fall off and little to no growth. Online it says that yellow leaves are due to iron deficiency. I think the Hollytone supplies this. I have never grown this plant before and would like advice on how to properly care for it. I have Christmas Carol camellias growing right next to them and they are thriving with lots of growth. I am at a loss of what more I could be doing for these poor plants. Any advice? Thank you.