|I have a large Rhodendrum 4 years old growing in a pot. Its very bushy and produces masses of white flowers. Of late i have noticed a lot of the leaves are turning yellow. Why is this and what should I do?
|There are several possible causes but after several years I would expect that the potting mix has deteriorated meaning the organic material has broken down and lost its ability to work as a sponge holding air and water, and so is no longer draining the way it should. If it is staying saturated and thus excluding air, this can cause root problems. Another possibility is that the soil has leached free of nutrients, so you may want to try repotting.