Rhododendron has brown leaves

Location, soil and weather damage

Despite proper care and optimal location can affect the rhododendron's brown leaves and spots. To take effective action, you have to know what causes the diseases.

Brown yellowish rolled up leaves - Rhododendron is thirsty:

Before the rhododendron dies of thirst, it rolls up its leaves. With this protective measure, it reacts to long dry periods in summer or to cold, dry winter weather.

What to do? Do not wet the leaves when watering to avoid sunburn. In winter only water on frost-free days so as not to cause frost damage. A layer of bark mulch keeps the root area frost-free for longer.

Rhododendron brown leaves and brown border - frost damage

With dry, cold and windy winter weather threatens with more sensitive, less hardy rhododendron varieties the risk of frost damage. Recognizable by dead flower buds or brown leaves and leaf margins.

What to do? Cover with fir twigs or reed mats as additional wind and cold protection.
More severe frost damage prune back in spring.

Brown yellowish leaf blades - sunburn

When sunburned, unshaded leaf blades turn brown-yellow. Shaded leaves show no damage.
What to do? Shade rhododendrons or transplant in a partially shaded location without the midday sun. Check the leaves regularly as the weakened plant is at risk of fungal attack.

Fungal and mold damage

Different shaped, brown spots on rhododendron leaves can cause up to 20 different fungi or rust and mold. Only a microscopic examination provides a detailed diagnosis of the cause.

Rhododendron brown leaves and brown buds

The cause are mostly fungal diseases like

• Phytophthora
• Botryosphaeria
• Phomopsis

All three fungal diseases spread quickly. But rarely threaten the entire plant. In the case of Phytophthora infestation, for example, the central ribs of the leaves turn brown. The infection spreads from the inside out and the leaves wither.

Brown tips, brown leaf margin - leaf spot disease:

The causes of this disease are different parasites of weakness. The first indications are irregular brown spots on the leaf margin or the leaf tip.

Brown spotted leaf tip with mold - gray mold rot:

If brown spots with a grayish mold coating appear from the tip of the leaf, it is gray mold rot. The infestation spreads over the entire leaf. There is a particularly high risk of infection in warm, humid weather

What to do? That helps preventively correct choice of locationcontrol, good plant nutrition and leaves. In the event of an infestation, treatment with fungicides is required every 10 days. Collect defective, discarded leaves and dispose of them with household waste.

Tips & Tricks

Steer clear of rhododendrons with brown leaves or yellow leaves, these are indicators of illness or lack of nutrients.