Troubleshooting
Common Rhododendron problems — and how to fix them
Common Rhododendron (Rhododendron ponticum) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Phytophthora ramorum (sudden oak death / ramorum blight)
R. ponticum is a major reservoir host for Phytophthora ramorum in the UK. Symptoms include leaf tip die-back and brown basal lesions. Report suspected cases to the relevant plant health authority; movement of infected plants is controlled.
Rhododendron lace bug (Stephanitis rhododendri)
Stippled, bleached upper leaf surfaces with brown excrement below indicate lace bug feeding. Treat with insecticide in spring when nymphs hatch. Improving air circulation reduces populations.
Bud blast (Seifertia azaleae)
Flower buds turn brown or silver and fail to open, covered in black bristle-like spore heads. Caused by a fungus spread by the rhododendron leafhopper. Remove and destroy infected buds; control leafhoppers with insecticide.
Prevent common rhododendron problems before they start
Most common rhododendron issues are care-mismatch, not bad luck. Dial in the basics:
Looking for common rhododendron in general rather than its problems? Read the full common rhododendron care guide — light, water, soil and feeding.
Common Rhododendron problems — FAQ
Why is my common rhododendron phytophthora ramorum (sudden oak death / ramorum blight)?
R. ponticum is a major reservoir host for Phytophthora ramorum in the UK. Symptoms include leaf tip die-back and brown basal lesions. Report suspected cases to the relevant plant health authority; movement of infected plants is controlled.
Why is my common rhododendron rhododendron lace bug (stephanitis rhododendri)?
Stippled, bleached upper leaf surfaces with brown excrement below indicate lace bug feeding. Treat with insecticide in spring when nymphs hatch. Improving air circulation reduces populations.
Why is my common rhododendron bud blast (seifertia azaleae)?
Flower buds turn brown or silver and fail to open, covered in black bristle-like spore heads. Caused by a fungus spread by the rhododendron leafhopper. Remove and destroy infected buds; control leafhoppers with insecticide.