Daylily Rust

Daylily rust is a highly contagious disease caused by the fungus Puccinia hemerocallidis, which primarily affects the foliage and flower stalks of daylilies (Hemerocallis spp.).
As the infection progresses, it disrupts photosynthesis, causes severe leaf yellowing, and can lead to complete foliar dieback; however, the disease rarely kills the entire plant.
How to Quarantine New Daylilies Safely
No daylily is 100% immune to rust.
  1. Isolate immediately: Keep new potted plants in a designated "holding zone" at least 10 to 15 metres away from your main garden beds for 4 to 6 weeks.
  2. Perform the tissue test: Wipe the underside of the leaves with a clean white paper towel. If it leaves a bright orange-yellow stain, rust is present.
  3. Inspect the pot: Look carefully under the pot rim and at the base of the plant where fungal spores like to hide.
  4. Water from below: Fill the saucer or water the soil directly during quarantine. Splashing water on the leaves will trigger the fast release of spores if the plant is a carrier.
You can effectively manage daylily rust without harsh synthetic chemicals by focusing on sanitation and cultural practices. The fungus needs moisture and living tissue to survive, so changing its environment is your best defense.
  • Cut back foliage: Remove all affected leaves at ground level immediately.
  • Destroy debris: Burn or bag infected leaves. Do not compost them.
  • Sanitise tools: Dip pruners in 70% isopropyl alcohol between plants.
  • Water the soil: Use drip irrigation. Keep the leaves completely dry.
  • Space out plants: Divide crowded clumps to increase airflow.
  • Apply biofungicides: Spray Bacillus subtilis preventatively on new growth.
  • Use copper sprays: Apply organic-approved copper fungicide early in spring.

Biogrow Copper Soap is a widely accessible in South Africa and is a certified organic product containing copper octanoate. It targets fungal spores like rust before they can settle into the leaf tissue.