I'm so sad. ALL my gardenias have leaves that are turning yellow and I don't know why. They're in three different parts of the garden/house, so the cause of this is a mystery. These are the ones on the side garden and all them are at different stages of yellowing, some more than others.
These are the gardenias in the middle garden and the ones closer to the house are a lot more yellow than the ones near the gate. The ones on the balcony are the same.
I've had a look at the soil and it's not too wet or too dry so that's not the issue. I also gave them all a dose of epsom salts in case it was magnesium sulphate deficiency and Seasol in case it was a nitrogen deficiency.
I also did a pH test of both lots of soil in the front garden and while one is a bit too neutral, the other is acidic - the perfect level for gardenias. The only thing I can think is an iron deficiency, so I gave them all a dose of iron chelate and prayed to the horticultural gods.
In the meantime, look at this beauty! They finally bloomed and they smell divine! These are on the balcony off the master bedroom and their perfume wafts into the room in the morning. Such a shame about these yellow leaves. I really hope all or one these things helps. I'll keep you posted.