HELP HELP PLEASE!!?!!

I had 15 gardenia plants in my flowerbed and now I'm down to 8. They get a little shade in the early morning but get full sun starting in the early afternoon and for the rest of the day. They have very little folage and what they do have turns yellow and the falls off. The plants have been in the ground for almost a year (the ones that are left), and I have one with a bud or two but that's it. They seem to be holding on for dear life. I have read a lot about cornmeal and epson salt but havn't tried it yet. I have use Miracle Grow for evergreen plants which I apply about once a month for two months now. I am just at a loss, please help!!

Thank you