Begonia rex-cultorum
Begonia rex-cultorum (Painted-Leaf Rex Begonia) Care Guide
Featured photobegonia-rex-cultorum.jpgBegonia rex-cultorum, sold as Painted-Leaf Rex Begonia, belongs to the rex group of Begonia and is grown indoors for its patterned foliage. A horticultural complex of Begonia rex hybrids selected for spectacular foliage in silver, purple, pink, red, and bronze, descended from a Himalayan species and developed in Victorian conservatories. Begonia thrive in bright filtered light, even moisture, and humidity above 50 percent, but they will not tolerate wet leaves overnight or stagnant air.
Care facts at a glance
- Light
- Bright indirect
- Water
- Water when the top 2 cm of mix has dried.
- Humidity
- 50–70 %
- Temperature
- 16–24 °C
- Soil
- Free-draining peat-based mix with extra perlite for aeration.
- Toxicity
- Mildly toxic if ingested. Tubers and below-ground parts contain soluble calcium oxalates. (humans) · Toxic to cats and dogs per ASPCA. Ingestion can cause kidney irritation and oral burning. (pets)
- Origin
- Tropical and subtropical regions of the Americas, Africa, and Asia.
- Mature size
- 20 to 60 cm tall depending on type, similar spread.
Overview
Begonia rex-cultorum is one of more than 2,000 species in Begonia, the sixth-largest plant genus. A horticultural complex of Begonia rex hybrids selected for spectacular foliage in silver, purple, pink, red, and bronze, descended from a Himalayan species and developed in Victorian conservatories. Begonia are divided horticulturally into rhizomatous, cane-stemmed, tuberous, and rex groups; this species belongs to the rex group.
Care Priorities
- Bright filtered light, never direct midday sun.
- Water at soil level when the top 2 cm of soil dries.
- Humidity above 50 percent — group with other plants or use a pebble tray.
- Good air circulation prevents powdery mildew and botrytis.
- Pinch growing tips on cane Begonia to encourage branching.
Common Problems
White powdery patches on leaves are powdery mildew — improve air flow and remove affected leaves immediately. Grey fuzzy patches are botrytis — reduce humidity and never water late in the day. Brown crispy edges signal dry air or under-watering.
Sources & further reading (3)
- encyclopedia — accessed 2026-04-28
- botanical-garden — accessed 2026-04-28
- toxicity-database — accessed 2026-04-28
Frequently asked questions
Why is my Rex Begonia going dormant?
Rex Begonia naturally goes semi-dormant in winter as day length shortens. Reduce watering, hold off on fertiliser, and accept some leaf loss. New growth resumes in spring as light returns.
How do I propagate a Begonia from a leaf?
Cut a healthy mature leaf with a section of petiole, slice the major veins on the underside, and lay the leaf flat on moist sphagnum or potting mix. New plantlets emerge from the cut veins within 4 to 8 weeks under high humidity.
Is Begonia toxic to pets?
Yes — Begonia is listed as toxic to cats and dogs by the ASPCA. The tubers (in tuberous types) are the most concentrated source of toxic calcium oxalates. Keep out of reach of pets that chew plants.
