Black-Eyed Susan Leaf Scorch: Drought or Disease?

Lower leaves drying and turning blackish-brown on budding black-eyed Susans (Rudbeckia) in summer heat usually indicates drought stress, not disease.

Diagnosis

• No pests visible → unlikely insect/virus.
• Rudbeckia is generally disease-resistant.
• Symptoms match moisture deficit: oldest leaves sacrificed first.

Remedy

1. Deep soak entire root zone (20 cm) immediately.
2. Apply half-strength liquid fertilizer to support flowering.
3. Mulch 5 cm to retain moisture.
4. Repeat weekly until regular rains return.

Prevention

• Consistent moisture during bud set and bloom.
• Morning watering at base.
• Divide crowded clumps every 3–4 years.

Plants typically recover quickly once hydrated.