The yellowing leaves sound like a lack of Magnesium. Give them 1 tblespoon per foot of height of epsum salts(Magnesium sulphate), available at most drup stores.You can sprinkle it around the drip line on the ground and water it in or put it in water and let it dissolve and pour it on. Do not fertilize them now, you don't want any new growth this close to winter. Wait til spring and give them some Hollytone, they'll love you for it.

Yellowing leaves are on going for this plant it seems. However, someone from the "line" said to feed it dry cornmeal, which I did, and even after the wrath of Ivan, my gardenia is all green and healthy peeping thru the debris. Last fall I put 2 cups of yellow meal around the bush, and then returned the mulch. Will do that again this fall, as soon as the tree cutters get the trees removed from over the gardenia.

I do appreciate both replies on this post. I will follow your advice and just bet the plant will do much better.

I think gardenias are tough. For every symptom, there is a long list of possibilities, and I'm not able to sort them out too well. Also, a lot of the choices are opposites (eg too much sun, too little sun). I would test the soil as a starter- at least you'll know its not a pH problem or some nutrient deficiency. Clemson.edu (Ag extension service)will have good info on this, but as I said, I have trouble sleuthing the list.

Gardenias take a lot of different things to make work.

You need to put acid in the soil and iron on the leaves. Spray Chleated Iron on the leaves everyone once in a while. Also coffee grounds or an acid fertilizer to make sure the pH of the soil is 6 or less.

Also make sure the area drains well. It is ok to water often, as long as the soil is drying out.