Identifying Rhododendron Diseases Identifying Rhododendron Diseases

Sometimes your rhododendron can get a little brown at the ends of the leaves, and others the flowers can wilt and wither away. So how can you tell if your rhododendron has a disease, and not just a marring that happens in nature? If you can identify the symptoms, you can pinpoint the disease and treat it promptly.

Root Rot and Stem Dieback

The soil beneath a rhododendron should be well drained. If it isn’t, the plant can contract root rot and stem dieback. The stems start to die from the tips downward because they’re not receiving the nutrients they need from the roots. Another symptom is yellowing leaves. By the time you see symptoms it’s typically too late to save your plant. The best treatment is prevention by keeping the drainage exceptional.

Flower Blight

Another common rhododendron disease, which is caused by high humidity combined with high heat is flower blight. This happens most often in the Southeastern U.S. Leaf water blisters, or petal water blisters, form when water collects on the petals, which then become soft and brown, literally decaying on the plant. Keep your plant sanitary by picking up dead plant matter and taking it away from the plant.

Leaf Spotting

Chemical burns, viral infections and fungal infections are all causes of leaf spotting. The most common viral infection is necrotic ring spotting, which is caused by a virus, and gives the leaves reddish, ring-shaped spots. Chemical burns cause the plant to yellow and brown, and can happen because of chemical drift (as when spraying other things with chemicals) and because of spraying the plant directly with chemicals. Fungal infections usually come from wetter weather, and so when the weather’s dry, the rhododendron can usually self-limit the advancement of the fungi.

Knowledge is power, and with knowing which diseases can afflict your rhododendron, you may be able to prevent them. The health of your rhododendron depends on you.

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