Sickly rhodies - Ask Extension
What is wrong with these rhodies. They are in a row of 6, 3 have similar issues. Some branches have die back and others have new growth. They are ov...
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Sickly rhodies #868799
Asked May 16, 2024, 7:23 PM EDT
What is wrong with these rhodies. They are in a row of 6, 3 have similar issues. Some branches have die back and others have new growth. They are over 60 years old, grown more like a tree, around 15’ tall. I have replenished rhodies before by cutting back severely but not sure with so much lichen and moss on the branches that they will generate new growth. Also not sure if the dieback is weather caused or some disease.
Multnomah County Oregon
Expert Response
I can’t offer a diagnosis of these plants. I don’t see obvious pest or disease on the photos you have shared. Moss and lichen are not usually a cause for concern about sprouting after pruning. However, I can’t say for sure these plants will sprout after rejuvenation pruning. The factors of plant health and age make it difficult to predict an individual plant’s reaction to pruning.
To offer a suggestion about care and reasons for the decline, share a few photos from more distance. The pattern of damage and surrounding plant and soil conditions may offer clues about what is happening.
The other thing that helps is a description of the site, care offered, history of pruning, watering, fertilizing, sun exposure, any changes in the environment, like a tree removed or a fast growing tree casting more shade, or ditches dug through root systems. Do the plants bloom heavily? Do you know when they were first pruned up into tree like forms? How are they mulched? Is there foot traffic around the plants? Rhododendrons are shallowly rooted and best not disturbed.
It sounds like a game of 20 questions, but the detective aspect of diagnosis can be long.
Another idea, since we can’t make a site visit, is to hire a certified arborist, who is able to see the area in person. For high value landscape plants it can be the best way to get assistance.
To offer a suggestion about care and reasons for the decline, share a few photos from more distance. The pattern of damage and surrounding plant and soil conditions may offer clues about what is happening.
The other thing that helps is a description of the site, care offered, history of pruning, watering, fertilizing, sun exposure, any changes in the environment, like a tree removed or a fast growing tree casting more shade, or ditches dug through root systems. Do the plants bloom heavily? Do you know when they were first pruned up into tree like forms? How are they mulched? Is there foot traffic around the plants? Rhododendrons are shallowly rooted and best not disturbed.
It sounds like a game of 20 questions, but the detective aspect of diagnosis can be long.
Another idea, since we can’t make a site visit, is to hire a certified arborist, who is able to see the area in person. For high value landscape plants it can be the best way to get assistance.
