What's wrong with my rhododendron?

[jleigh12]

We have a beautiful established rhododendron in the front of our house that has been healthy for years. For the last several months the plant has looked sicker and sicker. There were many branches where the leaves were olive green and rolled up and shriveling, like they were dying. Last week I pruned many of those off, being careful to sterilize the clippers after each cut. There are also many leaves that are turning yellow.

I only water this plant occasionally because of how well established it is and how well it has been doing for so many years. So I don't think it's overwatered. We did not have a particularly wet summer.

I wonder if there is root rot, and if so, what I should do about it.

I would be so sad if this plant died. Please let me know if there is anything else I should be doing!

This last photo is after I just trimmed off all the dying branches. I should have taken a before photo but I didn't think of it. Notice all the dead leaves on the ground.

 

[Chuck]

We have a beautiful established rhododendron in the front of our house that has been healthy for years. For the last several months the plant has looked sicker and sicker. There were many branches where the leaves were olive green and rolled up and shriveling, like they were dying. Last week I pruned many of those off, being careful to sterilize the clippers after each cut. There are also many leaves that are turning yellow.

I only water this plant occasionally because of how well established it is and how well it has been doing for so many years. So I don't think it's overwatered. We did not have a particularly wet summer.

I wonder if there is root rot, and if so, what I should do about it.

I would be so sad if this plant died. Please let me know if there is anything else I should be doing!

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This last photo is after I just trimmed off all the dying branches. I should have taken a before photo but I didn't think of it. Notice all the dead leaves on the ground.

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I am not an ornamental plant person. However, if this were a vegetable plant or fruit plant I would say it is a nutritional issue because of the mottling and yellow leaf green veins shown in the first two pictures. I would feed it with your normal NPK fertilizer and I would also feed it with either Liquid Iron or Iron Chelate. I don't see a fungal issue.

 

[YumYum]

Those leaves with greenish veins and reddish brown spots looked like my blueberries when the pH was too high. Sure enough when I look up rhododendrons, they like acid soil so I would check the soils pH level and get to adjusting it immediately. If the pH is too high, the plant cant uptake certain nutrients and I think that is what Chuck is seeing.

Walmart brand has an Azalea, Rhododendron fertilizer that is acidic and has iron in it. That is what I use on my blueberries but still you may have to add elemental sulfur to lower the pH. I have watered with 1/2 cup of distilled white vinegar per 2 gallon watering can to help lower the pH. Watering with city water is likely what is raising the pH over time because of the carbonates you are adding to the soil.