# Dying rhododendron



## Mozart (Jul 17, 2018)

One of 3 major branches on my rhododendron is dropping leaves quickly. This section is very "leggy" and has moss growing on the branch.

The leaves turn yellow, then orange, then fall off.

What's wrong - can this tree/branch be saved?


----------



## chrismar (May 25, 2017)

I'm not a rhody expert, but I will tell you the "moss" is called lichen, and it's generally harmless. It just uses the branch as a host while grabbing moisture from the air.

As for the leaves, it looks like some sort of disease or fungus. The rhody looks huge and old. Have you pruned it at all? If not, it might bounce back with a good pruning.


----------



## Mozart (Jul 17, 2018)

I did prune it in the spring and it did come back to life. I also fertalized with Holly Tone in May and last week.

I cut out dead/mostly dead branches but I must admit I'm not an expert in pruning.

We love this tree - not only is it beautiful when it blooms, it also provides privacy by blocking our front window. It would be a tradgedy if it dies!


----------



## chrismar (May 25, 2017)

Mozart said:


> I cut out dead/mostly dead branches but I must admit I'm not an expert in pruning.


Look up pruning videos by Cass Turnbull (RIP) of Plant Amnesty. She has excellent guides on how to prune almost anything.


----------



## Mozart (Jul 17, 2018)

Thanks @chrismar I will check her videos out.

I took a few pictures from inside the canopy.

Notice how the healthy branches do not have moss/lichen problems like the affected branch.

My irrigation system was blasting the branch in question and I do believe the harsh horizontal spray played a role. I will avoid running irrigation when possible, but I want to be more proactive to help the tree rebound!


----------



## rob13psu (May 20, 2018)

Could be this: https://ag.umass.edu/landscape/fact-sheets/rhododendron-leaf-spot


----------



## Mozart (Jul 17, 2018)

rob13psu said:


> Could be this: https://ag.umass.edu/landscape/fact-sheets/rhododendron-leaf-spot


Thanks for the reply, Rob, I appreciate it.

I spoke to one of the guys at SiteOne and he said it's root rot - too much water basically. He recommended a shot of Agri-FOS injected directly into the ground.

Also had an arborist come over and offer to inject fungicide for $150 (not sure which one). Backing off on water helped a lot, in retrospect this problem occurred after watering 5x/day for seeding project.

I'll probably have the arborist do the injection this time, and pay close attention. If it looks like something I can do myself I'll take over next year if needed.

On a side note I also need to treat my ash tree for Emerald Ash Borer (hopefully just as a preventative) :sad:


----------



## rob13psu (May 20, 2018)

Mozart said:


> rob13psu said:
> 
> 
> > Could be this: https://ag.umass.edu/landscape/fact-sheets/rhododendron-leaf-spot
> ...


No problem! I've had similar issues with my Azalea bonsai trees. They like moist, acidic, well draining soil, but hate having "wet feet". I have had to do chelated iron foliar treatments because my pH was too high and the plant had trouble with iron uptake. Adding peat and pine straw to the soil helped with that.

I have a large Ash tree in my back yard that was starting to lose foliage at the very top due to the Ash Borer. I had it injected this past spring ($250), and it has about 75% of the canopy left. I'd hate to have to take it down, but we'll see how it responds.

Good luck with your Rhody!


----------



## Miggity (Apr 25, 2018)

I'm pretty far off topic here, but there have been a couple mentions of Emerald Ash Borer and the incredibly high cost to treat/prevent. Many of us already own the AI to treat EAB via soil drench (Imidacloprid) in our grub control spray concentrates at higher (~10x) concentrations. Check the price on Adonis 2F or Dominion 2L. Depending on the size of your trees, you can treat for EAB for like $2/tree/year. See https://hort.uwex.edu/articles/homeowner-guide-emerald-ash-borer-insecticide-treatments/ for more info.


----------

