What is wrong with my Rhododendron plants? They have stopped flowering. I'm following the tips from the garden centre, NO GOOD.
Certified GKH Gardening Expert
It is probably a phosphorous deficiency. Add a phosphorous rich fertilizer or bone meal to the soil around the plants. Here is more information: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm