Troubleshooting
Arum Lily problems — and how to fix them
Arum Lily (Zantedeschia aethiopica) 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.
Rhizome Rot
Overwatering in cool or waterlogged conditions during winter dormancy causes fungal rot of the rhizome; allow soil to dry slightly between waterings from autumn onward and ensure good drainage outside the growing season.
Botrytis (Grey Mould)
Dense, humid conditions in mild wet weather encourage Botrytis cinerea on foliage and flowers; improve air circulation, remove affected material promptly, and avoid overhead watering.
Thrips
Western flower thrips cause silvery streaking on leaves and flower distortion in greenhouse or conservatory-grown plants; treat with an appropriate insecticide or introduce Amblyseius cucumeris as a biological control.
Prevent arum lily problems before they start
Most arum lily issues are care-mismatch, not bad luck. Dial in the basics:
Arum Lily problems — FAQ
Why is my arum lily rhizome rot?
Overwatering in cool or waterlogged conditions during winter dormancy causes fungal rot of the rhizome; allow soil to dry slightly between waterings from autumn onward and ensure good drainage outside the growing season.
Why is my arum lily botrytis (grey mould)?
Dense, humid conditions in mild wet weather encourage Botrytis cinerea on foliage and flowers; improve air circulation, remove affected material promptly, and avoid overhead watering.
Why is my arum lily thrips?
Western flower thrips cause silvery streaking on leaves and flower distortion in greenhouse or conservatory-grown plants; treat with an appropriate insecticide or introduce Amblyseius cucumeris as a biological control.