Troubleshooting
California poppy problems — and how to fix them
California poppy (Eschscholzia californica) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Powdery mildew
Appears in humid, crowded conditions late in the season. Improve airflow by thinning plants to 15 cm apart and avoiding overhead watering. Remove affected foliage promptly.
Failure to germinate
Seeds require a cold period and light to germinate; do not cover deeply. Direct-sow in autumn or early spring onto prepared soil and barely rake in. Transplant shock from pot-grown plants often causes failure.
Short bloom period in heat
Plants go dormant or die back in summer heat above 30°C. Successive autumn and early-spring sowings extend the season. Self-sown seedlings often outperform transplants.
Prevent california poppy problems before they start
Most california poppy issues are care-mismatch, not bad luck. Dial in the basics:
Looking for california poppy in general rather than its problems? Read the full california poppy care guide — light, water, soil and feeding.
California poppy problems — FAQ
Why is my california poppy powdery mildew?
Appears in humid, crowded conditions late in the season. Improve airflow by thinning plants to 15 cm apart and avoiding overhead watering. Remove affected foliage promptly.
Why is my california poppy failure to germinate?
Seeds require a cold period and light to germinate; do not cover deeply. Direct-sow in autumn or early spring onto prepared soil and barely rake in. Transplant shock from pot-grown plants often causes failure.
Why is my california poppy short bloom period in heat?
Plants go dormant or die back in summer heat above 30°C. Successive autumn and early-spring sowings extend the season. Self-sown seedlings often outperform transplants.