Hon just had a nursery iinstall our entrance sun bed incouding three gardenia shrubs whose leaves are turning yellow. They have not been in over two weeks. What to do??
At first I thought they needed water. But there are more yellow leaves than before. Somewhere I read something about adding iron, epsom salts and yellow corn meal. Althought we're in the south I can't get any yellow cornmeal but the other two I have. But want to make sure Im doing the right thing.
It's probably just transplant shock. I doubt at this point that it's a nutrient deficiency (unless they already looked unhealthy before they were planted). You might try rigging up some shade for them for a few weeks to protect them from the hot sun while they're trying to get established, and check on your watering by sticking a finger down a couple inches into the soil near the roots and see how wet it feels. If it's sopping wet then you don't want to water, but you don't want to let them dry out.
I have one gardenia that I've been caring for over ten years and have been through quite a few things with it, especially whiteflies, but on the whole they are pretty sturdy plants. I wonder if somehow the nurserymen injured your plants while planting them - were they J-rooted or had too many roots damaged? Have you contacted the nursery? It seems they should help. Perhaps the plants they gave you were not vigorous.
I got so annoyed with a couple of gardenias that I dug them up and sent them to bad plant area in my back yard. Mine were yellow most of the time and I try everything, usually yellow means lack of iron but in your case your plants haven't had time to yellow up from lack of iron. I would make sure they aren't getting over watered first and also gardenias don't like the sun all that much so you might want to think about how much sun they are getting. Here's a strange thing, my neighbor has two different varieties of gardenias along one side of his house. Three of them are huge and dark green all year and three are the yellow color mine always were. He wasn't the one who planted them so he doesn't know names which is too bad because the one type of gardenia seems to love our climate the others simply don't.