Troubleshooting
Madonna White Snapdragon problems — and how to fix them
Madonna White Snapdragon (Antirrhinum majus) 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.
Antirrhinum rust
The key disease risk; pale spots on upper leaves, orange pustules below; remove and destroy infected material, apply preventative fungicide from midseason.
Botrytis (grey mould)
Attacks spent white flowers particularly in wet weather as white petals are hard to spot early; remove faded spikes promptly.
Aphids
Cluster on soft new tips; treat with insecticidal soap at first sign.
Powdery mildew
Appears on older foliage when plants are stressed by heat or dry soil; maintain even moisture.
Slugs and snails
Damage seedlings and soft growth at the base; use iron phosphate pellets around young transplants.
Prevent madonna white snapdragon problems before they start
Most madonna white snapdragon issues are care-mismatch, not bad luck. Dial in the basics:
Madonna White Snapdragon problems — FAQ
Why is my madonna white snapdragon antirrhinum rust?
The key disease risk; pale spots on upper leaves, orange pustules below; remove and destroy infected material, apply preventative fungicide from midseason.
Why is my madonna white snapdragon botrytis (grey mould)?
Attacks spent white flowers particularly in wet weather as white petals are hard to spot early; remove faded spikes promptly.
Why is my madonna white snapdragon aphids?
Cluster on soft new tips; treat with insecticidal soap at first sign.
Why is my madonna white snapdragon powdery mildew?
Appears on older foliage when plants are stressed by heat or dry soil; maintain even moisture.
Why is my madonna white snapdragon slugs and snails?
Damage seedlings and soft growth at the base; use iron phosphate pellets around young transplants.