Rex Begonia
Begonia rex · the King Begonia
Its wild ancestor grows on shaded, humid, rocky forest slopes of the Eastern Himalaya. It is grown almost entirely for its swirled, metallic, multicoloured leaves, not for its small, forgettable flowers.
Family
Begoniaceae
Origin
Eastern Himalaya
In the wild
Shaded rocky slopes
Indoors
30–45 cm
Growth
Slow to moderate
With pets
Toxic
Where it's from
The Eastern Himalaya
Himalayan forest floor
The parent species ranges from Assam across southern Bhutan, southern China, northern Myanmar and Vietnam.
Outdoors: zones 10–11
Frost-tender. It cannot take frost or direct sun, so almost everywhere it lives indoors.
Not at risk
The wild parent is widespread and not flagged as threatened, even as many other begonias are.
Barely a species at all
The original arrived in 1850s England as a stowaway among orchid shipments from Assam. From that one import, breeders spun off more than 500 named cultivars of swirled, metallic leaves. You can clone a whole new plant just by slashing one leaf's veins and pinning it to soil.
An orchid-crate stowaway
The first plant reached England hidden among orchid shipments from Assam.
500+ cultivars
From that single import grew a sprawling hybrid swarm of named forms.
Cloned from a leaf
Slash one leaf's veins, pin it down, and plantlets sprout straight from the cuts.
How to keep it
LightBright, indirect
East or west windows. Direct sun scorches and fades the leaves, so keep it filtered.
WaterLightly, evenly moist
Let the surface almost dry between waterings. Never soggy, and never wet the leaves or crown.
HumidityHigh, above 50%Dry air is the main reason it fails. Use a pebble tray or group plants, but do not mist the leaves.
Temperature16–21°CWarm and steady. Keep it above about 13°C in winter and away from cold drafts.
SoilLight, free-drainingA porous mix in a wide, shallow pot, since the rhizome runs sideways and roots are shallow.
FeedingGrowing seasonA weak balanced feed roughly every two weeks in active growth, easing off in winter.
DifficultyHardModerate to hard. It needs humidity, dry foliage, and patience through dormancy.
With petsToxicCalcium oxalates, most concentrated in the rhizome. Vomiting and oral irritation if chewed.
PropagationLeaf cuttingsThe classic begonia trick. Nick a leaf's veins and pin it to moist mix, or divide the rhizome.
RepottingEvery 1–2 yearsIn spring, into a shallow pot only slightly larger. Divide the rhizome if crowded.
What the data says
What it costs
Affordable and mass-propagated from leaf cuttings, with a modest collector layer.
$8–20
Newer or slower cultivars run $20–40 and up. No Monstera-style bubble, because it roots so easily from a leaf.
IUCN · Not assessed
In the wild
The inverse of the vanishing-houseplant tale: this one is essentially a human invention.
The plant on millions of windowsills is a 170-year-old hybrid swarm bred from a still-secure wild Assam species. We multiplied it into more than 500 leaf-cloned cultivars without endangering its ancestor. The drama here is taxonomic, not conservational: it barely qualifies as a species.
When it sulks
Crispy brown leaf edgesLow humidity, the classic rex complaint. Raise ambient humidity, but do not mist.
Powdery mildewWhite dusty patches from wet leaves, poor airflow and crowding. Keep foliage dry, improve air.
Grey mould or crown rotOverwatering and cold, damp conditions. Ease off water and improve airflow.
Yellowing and collapseOverwatering and root rot, or natural winter dormancy. Water sparingly until spring.
PestsMealybugs, aphids and red spider mite, which thrive in the dry air it hates.
Varieties & company
The varieties
EscargotFireworksSilver QueenHarmony's Red Robin
Pairs with · keep apart from
FernsCalatheaFittoniaSnake PlantZZ PlantAloe
A new plant, every week.
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