Rhododendron - Ask Extension
What is wrong with this Rhododendron?
Knowledgebase
Rhododendron #871945
Asked June 06, 2024, 5:35 PM EDT
What is wrong with this Rhododendron?
Clackamas County Oregon
Expert Response
Thank you for your question. The white spots on the bark are lichens, which do not harm your plant. https://s3.wp.wsu.edu/uploads/sites/2073/2014/03/110207.pdf
However, they may be an indication that your plant is stressed and/or in decline. It certainly could benefit from pruning.
The spots or streaking (I can't tell which) on the leaves is more problematic, and a diagnosis can't be made just from photos. I suggest that you send leaf and soil samples to the OSU Plant Clinic, where they can be tested. It may be a nutrient deficiency, or there may be a disease, especially one in the soil. Here is the Clinic's information: https://bpp.oregonstate.edu/how-submit-plant-materials
Good luck!
However, they may be an indication that your plant is stressed and/or in decline. It certainly could benefit from pruning.
The spots or streaking (I can't tell which) on the leaves is more problematic, and a diagnosis can't be made just from photos. I suggest that you send leaf and soil samples to the OSU Plant Clinic, where they can be tested. It may be a nutrient deficiency, or there may be a disease, especially one in the soil. Here is the Clinic's information: https://bpp.oregonstate.edu/how-submit-plant-materials
Good luck!
