I've had a Pieris japonica 'Flaming Silver' in a woodland setting now for two years (under deciduous trees in clay soil but have been trying to amend it with good organic compost) and this winter half the plant died off while the rest of the plant survived and even put out new growth. I'm assuming that the plant needs to be in a more porous soil and that its feet are too wet. I was going to amend the soil with lots of peat moss and compost and give it a shot of 6-8-6. Any other advice or suggestions that could help bring my little Pieris back up to health?
Assuming root rot IS the problem lift and replant in more suitable soil. Mixing in sand could help if alot is used, whole rooting area for years is treated. Compost decomposes and returns you to original condition. Bringing in coarser soil and dumping it on top of existing soil, planting in that more to the point. Fertilizer should follow a soil test, won't necessarily assit with a root rot problem--likewise changing the soil would not be expected to remove an existing infestation. "Fungicidal"* drench may be required, even then we are talking about control rather than eradication. *Water molds not actually fungi
