Troubleshooting
Candle larkspur problems — and how to fix them
Candle larkspur (Delphinium elatum) 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
Common in dry, warm conditions or crowded plantings. Improve airflow by adequate spacing (60 cm apart), water at the base, and apply a fungicide if severe. Resistant cultivars are available.
Slugs and snails
Attack emerging shoots in spring, causing ragged holes or complete destruction of young growth. Use organic slug pellets or beer traps; apply copper tape around crowns as a barrier.
Crown rot (Sclerotinia)
Causes stems to collapse at the base in wet conditions. Ensure free-draining soil and never allow crowns to sit in standing water. Remove and destroy affected plants; do not replant delphiniums in the same spot.
Prevent candle larkspur problems before they start
Most candle larkspur issues are care-mismatch, not bad luck. Dial in the basics:
Looking for candle larkspur in general rather than its problems? Read the full candle larkspur care guide — light, water, soil and feeding.
Candle larkspur problems — FAQ
Why is my candle larkspur powdery mildew?
Common in dry, warm conditions or crowded plantings. Improve airflow by adequate spacing (60 cm apart), water at the base, and apply a fungicide if severe. Resistant cultivars are available.
Why is my candle larkspur slugs and snails?
Attack emerging shoots in spring, causing ragged holes or complete destruction of young growth. Use organic slug pellets or beer traps; apply copper tape around crowns as a barrier.
Why is my candle larkspur crown rot (sclerotinia)?
Causes stems to collapse at the base in wet conditions. Ensure free-draining soil and never allow crowns to sit in standing water. Remove and destroy affected plants; do not replant delphiniums in the same spot.