Troubleshooting
Begonia 'Emerald Giant' problems — and how to fix them
Begonia 'Emerald Giant' (Begonia rex-cultorum 'Emerald Giant') 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
Rex begonias mildew in stagnant, humid air. Improve airflow, keep foliage dry, and remove affected leaves.
Leaf scorch
Direct sun burns and fades the large leaves. Move to bright indirect light.
Rhizome and root rot
Overwatering or a buried rhizome causes soft, blackened rot. Keep the rhizome surface-set and let the topsoil dry between waterings.
Winter leaf drop
Rex begonias may shed leaves and semi-dormant in winter. Reduce water, stop feeding, keep warm, and growth resumes in spring.
Prevent begonia 'emerald giant' problems before they start
Most begonia 'emerald giant' issues are care-mismatch, not bad luck. Dial in the basics:
- Common rex begonia problems — the species this cultivar belongs to
- What's wrong with my plant? — the diagnosis apps compared
- Begonia 'Emerald Giant' watering schedule
- Begonia 'Emerald Giant' light requirements
- Best soil mix for begonia 'emerald giant'
- Begonia 'Emerald Giant' temperature & humidity
- Full begonia 'emerald giant' care guide
Looking for the species overview? Begonia — the full care guide.
Begonia 'Emerald Giant' problems — FAQ
Why is my begonia 'emerald giant' powdery mildew?
Rex begonias mildew in stagnant, humid air. Improve airflow, keep foliage dry, and remove affected leaves.
Why is my begonia 'emerald giant' leaf scorch?
Direct sun burns and fades the large leaves. Move to bright indirect light.
Why is my begonia 'emerald giant' rhizome and root rot?
Overwatering or a buried rhizome causes soft, blackened rot. Keep the rhizome surface-set and let the topsoil dry between waterings.
Why is my begonia 'emerald giant' winter leaf drop?
Rex begonias may shed leaves and semi-dormant in winter. Reduce water, stop feeding, keep warm, and growth resumes in spring.