Rex and rhizomatous Begonias are grown for their foliage rather than flowers. In nature, they grow as low, spreading plants in sheltered, humid environments, often across leaf litter and shaded forest floors.
Indoors, their performance is shaped by the same factors as other humidity-dependent plants: stable moisture, filtered light, and consistent conditions.
Light
Begonias prefer bright, indirect light.
They require more light than many people expect. In low light, growth slows and colour becomes dull. Direct sun should be avoided, as the leaves scorch easily.
- Bright, filtered light → ideal
- Low light → reduced growth and colour
Water
Begonias require even moisture, but do not tolerate excess water.
The rhizome sits at or just below the surface, making it sensitive to both drying out and rot. The aim is to keep the mix lightly moist without becoming wet or stagnant.
- Water when the surface begins to dry
- Avoid allowing the mix to fully dry out
- Avoid keeping the pot constantly wet
Overwatering is one of the most common causes of failure, particularly in dense or poorly draining mixes.
Humidity
Rex and rhizomatous Begonias benefit from moderate to high humidity.
In dry air, leaf edges may crisp and overall growth declines. However, unlike some terrarium plants, they also require airflow to prevent leaf and stem issues.
They perform well in:
- Bright bathrooms
- Open terrariums or cabinets with airflow
- Sheltered indoor positions with stable conditions
Temperature
Begonias prefer stable, warm temperatures.
- Ideal range: 18–26°C
- Avoid cold conditions and sudden temperature changes
Growing Medium
A light, well-draining mix is essential.
The mix should retain some moisture while allowing excess water to drain freely. A combination of organic material and drainage components such as perlite or bark works well.
Growth Habit
Rex and rhizomatous Begonias grow from a creeping rhizome.
This rhizome spreads across the surface of the soil, producing leaves along its length. Over time, plants widen rather than grow taller.
- Best suited to shallow or wide containers
- Can be divided easily as they spread
Common Issues
Leaf edges browning
Usually caused by low humidity or inconsistent watering.
Soft stems or base rot
Typically the result of excess moisture or poor drainage.
Leaves collapsing
Can occur from either overwatering or sudden drying. Stability is more important than frequency.
Dull colour
Usually linked to insufficient light.
Where Begonias Work Best
Rex and rhizomatous Begonias perform best in environments that balance humidity with airflow.
- Bright indoor areas with stable conditions
- Enclosed spaces with ventilation
- Open terrariums rather than sealed environments
They are less suited to very dry or highly fluctuating indoor conditions.
Summary
Rex and rhizomatous Begonias are not difficult, but they are sensitive to imbalance.
When grown with bright, indirect light, stable moisture, and moderate humidity with airflow, they perform reliably. When conditions become too wet, too dry, or too stagnant, they decline quickly.
Related Reading
For a comparison with other humidity-dependent plants, see:
