Troubleshooting
Azalea 'Gibraltar' problems — and how to fix them
Azalea 'Gibraltar' (Rhododendron 'Gibraltar') 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.
Lime-induced chlorosis
Yellow leaves with green veins indicate alkaline soil or hard water. Apply sequestered iron or re-pot into ericaceous compost; water with rainwater.
Rhododendron powdery mildew
White or pale patches on leaves. Improve airflow, reduce overhead watering, and apply a suitable fungicide.
Vine weevil
Adult beetles notch leaf edges; larvae destroy roots. Apply nematode biological controls in late summer and autumn.
Bud blast
Flower buds turn brown and fail to open, caused by Pycnostysanus azaleae transmitted by leafhoppers. Control leafhoppers with insecticide in late summer.
Waterlogging
Fibrous roots rot quickly in poorly drained ground. Improve drainage before planting; raise the planting level slightly if drainage is borderline.
Prevent azalea 'gibraltar' problems before they start
Most azalea 'gibraltar' issues are care-mismatch, not bad luck. Dial in the basics:
Azalea 'Gibraltar' problems — FAQ
Why is my azalea 'gibraltar' lime-induced chlorosis?
Yellow leaves with green veins indicate alkaline soil or hard water. Apply sequestered iron or re-pot into ericaceous compost; water with rainwater.
Why is my azalea 'gibraltar' rhododendron powdery mildew?
White or pale patches on leaves. Improve airflow, reduce overhead watering, and apply a suitable fungicide.
Why is my azalea 'gibraltar' vine weevil?
Adult beetles notch leaf edges; larvae destroy roots. Apply nematode biological controls in late summer and autumn.
Why is my azalea 'gibraltar' bud blast?
Flower buds turn brown and fail to open, caused by Pycnostysanus azaleae transmitted by leafhoppers. Control leafhoppers with insecticide in late summer.
Why is my azalea 'gibraltar' waterlogging?
Fibrous roots rot quickly in poorly drained ground. Improve drainage before planting; raise the planting level slightly if drainage is borderline.