Troubleshooting
Heavy Begonia problems — and how to fix them
Heavy Begonia (Begonia ponderosa) 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 white, dusty fungal coating on leaf surfaces is common when air circulation is poor or foliage is kept damp. Improve ventilation, water at soil level only, and remove affected leaves; a dilute bicarbonate of soda spray can slow spread.
Rhizome rot
The creeping rhizome blackens and collapses when compost is kept waterlogged or the plant is grown in a pot without drainage holes. Allow the surface to dry between waterings, ensure free drainage, and repot into fresh, airy compost if rot is found, cutting back to healthy tissue.
Mealybugs
White, waxy clusters appear in leaf axils and along the rhizome. Remove by dabbing with a cotton bud dipped in rubbing alcohol, or apply insecticidal soap; check regularly as infestations spread quickly in warm, humid conditions.
Prevent heavy begonia problems before they start
Most heavy begonia issues are care-mismatch, not bad luck. Dial in the basics:
Heavy Begonia problems — FAQ
Why is my heavy begonia powdery mildew?
A white, dusty fungal coating on leaf surfaces is common when air circulation is poor or foliage is kept damp. Improve ventilation, water at soil level only, and remove affected leaves; a dilute bicarbonate of soda spray can slow spread.
Why is my heavy begonia rhizome rot?
The creeping rhizome blackens and collapses when compost is kept waterlogged or the plant is grown in a pot without drainage holes. Allow the surface to dry between waterings, ensure free drainage, and repot into fresh, airy compost if rot is found, cutting back to healthy tissue.
Why is my heavy begonia mealybugs?
White, waxy clusters appear in leaf axils and along the rhizome. Remove by dabbing with a cotton bud dipped in rubbing alcohol, or apply insecticidal soap; check regularly as infestations spread quickly in warm, humid conditions.