Rex begonia Begonia rex
Rex begonia (Begonia rex) is an evergreen perennial flowering plant in the Begoniaceae family, native to NE India (Assam), southern China and Vietnam (moist, shady montane forest). It grows 30–50 cm (12–20 in) tall and 30–60 cm (12–24 in) wide, wants shade and moderate water, and is hardy to about 10 °C (50 °F). Space plants about 35 cm (14 in) apart.
Plan Rex begonia in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Rex begonia at a glance
| Type | Perennial flowering plant, evergreen |
|---|---|
| Family | Begoniaceae |
| Mature height | 30–50 cm (12–20 in) |
| Mature spread | 30–60 cm (12–24 in) |
| Spacing | 35 cm (14 in) centre to centre |
| Sun | Shade, at least 1 h of direct sun a day |
| Water | Moderate; drought tolerance none, waterlogging tolerance none |
| Soil pH | 5.5–6.5 |
| Cold hardiness | About 10 °C (50 °F) once established (roughly USDA zone 12) |
| Heat stress | Likely above about 29 °C (84 °F) |
| Flowering | from about May for 4–9 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | None |
| Pollinator value | Low |
| Edible | Not grown as food |
| Native to | NE India (Assam), southern China and Vietnam (moist, shady montane forest) |
| Common in gardens of | 🇨🇳 China, 🇸🇬 Singapore |
Is Rex begonia toxic?
- People: mildly toxic
- Cats: mildly toxic
- Dogs: mildly toxic
- Parts: tubers, rhizome, leaves
Begonias contain insoluble calcium oxalates; mouth irritation and vomiting in pets (ASPCA).
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Rex begonia
No well-documented helpful pairing. Group it with plants that like shade and moderate water.
See Rex begonia in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- Gardens by the Bay (26 plants)
- Monet’s gardens at Giverny (6 plants)
Questions about Rex begonia
- How far apart should I plant Rex begonia?
- About 35 cm (14 in) apart, centre to centre. A mature plant spreads 30–60 cm (12–24 in).
- Does Rex begonia need full sun?
- Shade: at least 1 hours of direct sun a day.
- How much water does Rex begonia need?
- Moderate water. Drought tolerance is none and waterlogging tolerance none.
- How cold-hardy is Rex begonia?
- It tolerates about 10 °C (50 °F) once established, roughly USDA zone 12.
- When does Rex begonia flower?
- From about May for 4–9 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Rex begonia poisonous to cats and dogs?
- For cats it is mildly toxic; for dogs mildly toxic; for people mildly toxic. Begonias contain insoluble calcium oxalates; mouth irritation and vomiting in pets (ASPCA).
- What grows well with Rex begonia?
- There is no well-documented companion pairing for Rex begonia. Group it with plants that like the same sun (shade) and water (moderate).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
- Cloud Forest conservatory (Cloud Mountain, cool-moist montane climate), Gardens by the Bay
Notes and assumptions
- Tropical montane (cloud forest, about 1,000–3,000 m): needs cool, constantly humid air. In the hot lowlands it is grown in a cooled conservatory (as in the Cloud Forest dome, kept near 23–25 °C).
- Grown for its asymmetric, silver-zoned and purple-flushed leaves; small pink flowers.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Wax begonia Begonia semperflorens-cultorum
- Polka-dot begonia (spotted begonia) Begonia maculata
- Sunflower Helianthus annuus
- French marigold Tagetes patula
- English lavender Lavandula angustifolia
- Zinnia Zinnia elegans
- Cosmos Cosmos bipinnatus
- Purple coneflower Echinacea purpurea