Temperature
60–80°F
Keep away from winter window glass and heating vents.
Rex begonia
Begonia rex
Rex begonia wants medium light and water every 5 to 10 days, once the top inch is dry. Toxic to cats, dogs, and humans.
Light
Medium
LowMediumBright indirectDirect
Three feet back from an east or north window. Direct sun bleaches the metallic patterning it is grown for.
Water
Every 5–10 days
Baseline for a 6-inch pot indoors. Check first: water when the top inch is dry, not on a schedule.
Humidity
50% and up
Wants 70%. Struggles in dry winter air.
Difficulty
Demanding
Scores 4 of 5: Scores 4 of 5: it wants high humidity and hates water on its leaves, which rules out most of the ways people raise humidity. It also dies back in winter and regrows from the rhizome, which people mistake for death.
Habit
Clumping
Grows to 8–18 inches. No support needed.
Toxic to cats, dogs, and humans
Contains soluble calcium oxalates. Reported signs include oral irritation, vomiting, difficulty swallowing.
If a pet has chewed a leaf, rinse the mouth with water and call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
Full detail for cats → Full detail for dogs →
What each authority says
- ASPCA
- Toxic to cats and dogs · soluble calcium oxalates
- NC State Extension
- Entry exists and records no poison data.
Light
Medium light. Three feet back from an east or north window. Direct sun bleaches the metallic patterning it is grown for.
Water
Every 5 to 10 days in a 6-inch pot, when the top inch is dry.
Treat the interval as a starting point and the test as the actual instruction. Pot size, light level and season all move the number.
| Method | soak and dry |
|---|---|
| Test before watering | the top inch is dry |
Soil and potting
Two parts peat-free potting soil, one part perlite, one part fine bark.
Repot roughly every 1.5 years, or when roots come through the drainage holes and water runs straight through without absorbing.
Common problems
Ranked by how often each turns out to be the cause for this species. Each links to a diagnosis page with the causes ranked for this species.
- Brown crispy edges monitor
- Leaf drop this week
Pest and disease guidance for this species consulted at the Missouri Botanical Garden Plant Finder, checked 2026-09-12.
Pests
Recorded for this species. Each links to identification and treatment.
- Mealybugs this week
- Thrips act today
- Spider mites act today
- Powdery mildew this week
Propagation
Leaf cutting in soil. Roots in 28 to 56 days.
| Preferred method | leaf cutting |
|---|---|
| Medium | soil |
| Time to root | 28–56 days |
| Node required | No |
| Best season | Spring and summer |
Sources
- ASPCA Animal Poison Control — Begonia rex Checked 2026-09-12.
- North Carolina Extension Gardener Plant Toolbox — Begonia rex (consulted; entry exists and records no poison data.) Checked 2026-09-12.
- Wikidata entity Q2893850 — taxonomy and entity identity.
- Royal Botanic Gardens Kew, Plants of the World Online — Begonia rex Checked 2026-09-12.
- Missouri Botanical Garden Plant Finder — Begonia rex Pest and disease guidance. Checked 2026-09-12.
- Photograph: NasserHalaweh, Wikimedia Commons , CC BY-SA 4.0.
Compiled and edited by Tony Valcarcel · 2026-09-02
Tony Valcarcel is the editor and publisher of this database, not a horticulturist
or a veterinarian. Every fact above is drawn from the sources listed, and
toxicity severity is reported only where one of them stated it.
How this is sourced.
Last updated 2026-09-02