Powdery Mildew? Don’t Panic — Just Be Proactive.

Powdery mildew is becoming more common in NZ gardens, especially on fragrant rhodos like Princess Alice, John Bull, and Trewithian Orange. It shows up as yellow blotches on the top of leaves, followed by fuzzy white spores underneath — and if left untreated, it can spread fast.

Why it happens:
Warm, humid conditions (especially without dew)
Overcrowded or shaded plants
Poor air circulation

What to do:
Spray in spring as new growth appears - Try alternating Kumulus® DF (1g/L) and Yates Fungus Fighter for best results
Prune to improve airflow
Keep leaves dry when watering
Clean up infected leaves in autumn to prevent reinfection
Choose mildew-resistant varieties when planting

Powdery mildew won’t kill your rhododendrons, but it can weaken them. Catch it early and your plants will bounce back stronger and healthier!