Troubleshooting
Belladonna larkspur problems — and how to fix them
Belladonna larkspur (Delphinium x belladonna) 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
A persistent problem in warm, dry, or humid still-air conditions. Space plants at least 50–60 cm apart, water at the base, and treat with a potassium bicarbonate or sulfur spray at the first sign of infection.
Crown rot
Waterlogged soil at the crown causes collapse and death. Ensure excellent drainage; avoid mulching directly against the crown. Do not replant delphiniums in previously infected soil.
Slugs and snails
Emerging shoots in spring are highly attractive to slugs. Apply iron phosphate pellets around the crowns at emergence, and use beer traps or physical barriers to protect young growth.
Prevent belladonna larkspur problems before they start
Most belladonna larkspur issues are care-mismatch, not bad luck. Dial in the basics:
Looking for belladonna larkspur in general rather than its problems? Read the full belladonna larkspur care guide — light, water, soil and feeding.
Belladonna larkspur problems — FAQ
Why is my belladonna larkspur powdery mildew?
A persistent problem in warm, dry, or humid still-air conditions. Space plants at least 50–60 cm apart, water at the base, and treat with a potassium bicarbonate or sulfur spray at the first sign of infection.
Why is my belladonna larkspur crown rot?
Waterlogged soil at the crown causes collapse and death. Ensure excellent drainage; avoid mulching directly against the crown. Do not replant delphiniums in previously infected soil.
Why is my belladonna larkspur slugs and snails?
Emerging shoots in spring are highly attractive to slugs. Apply iron phosphate pellets around the crowns at emergence, and use beer traps or physical barriers to protect young growth.