Rhododendrons

Question

In general, what should be a yearly cycle of care? I read so much, and most suggestions is too late for diseases. Name mulches, too. I read opposites: peat moss, then NO, it forms a water resistant surface. A yearly care for Roseum Elegans? Rhodo from the ground up, mulching to disease? Best timings, too. I have a very old plant that I listed above with 6 really long woody branches rising 9 feet long. I have the dreaded die back and I cannot see the diseases that all the photos show. It is terrible. I have half of this huge front of house plant, and I could not get help in time. Penn State (I live in Pittsburgh, PA ) says no chemical will help. I fear I have left the long branches that experience loss of leaves, but will the disease go down farther into the thick part? I have a hideous large hole in the middle now because no matter where I look there seems to be no answer. Do I start fresh, or can I really salvage the plant by severe cut back now? My rhodie looks like a ring of green with a hole in the middle now.

Answer 1

This article will help you with plant care:
http://www.rhododendron.org/plantcare.htm

Rhododendron "die-back" refers to several fungal diseases that attack rhododendrons. Phytophthora root rot is one common cause of die-back of the aboveground parts of the plant. Botryosphaeria disease is another.

https://www.ces.ncsu.edu/depts/pp/notes/oldnotes/od12.htm#die

This article is about the related azaleas, but the advice applies to rhododendrons too:
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/phytophthora-root-rot-azaleas.htm