I have 5 gardenias planted along a SW facing wall that gets afternoon sun and is well drained. I have feed them with blood and bone and dynamic lifter and they are well watered. However three of them have quite a few yellow leaves. Are they lacking some chemical?
11 January 2019 11:34 AM
if it is older leaves yellowing it is perhaps a shortage of nitrogen, new leaves yellowing it could be iron, if all over then maybe magnesium. With the fertilisers you have used thay should not be lacking so I am thinking your pH is probably wrong. Suggest get a pH test kit from your nursery and make sure soil is in the acid range around pH 5.5 to 6.5. A fast acting liquid such as Aquasol Soluble Plant Food used occasionally will support the other 2 slow acting fertilisers.