Rex Begonia
Begonia rex-cultorum hybrids
Through the year 🗓️
☀️ Summer now
Keep it out of hot direct sun and boost airflow to stay ahead of powdery mildew.
🍂 Fall
Taper water and feed as growth slows and some leaves thin out. That's normal.
❄️ Winter
Water sparingly and tolerate a scruffy semi-dormant look; it rebuilds from the rhizome in spring.
🌱 Spring
Repot shallow and wide, divide the rhizome if crowded, and restart gentle feeding.
The details
Light & placement
- Light
- Bright indirect; strong enough light to fuel the leaf color, never direct sun
- Ideal PPFD
- 100–250 µmol·m⁻²·s⁻¹
- Grow-light distance
- 18–24 in below LED
Water & feed
- Watering method
- Water when the top inch is dry, aiming at the soil, because wet leaves invite powdery mildew. Slightly underwatered beats soggy every time; the rhizome rots fast.
- Fertilizer
- Balanced feed at ¼–½ strength every 2–4 wks in spring–summer.
Home & habit
- Soil
- Light, airy mix with lots of perlite; pH 5.7–6.2
- Humidity
- High (50–60%) but with moving air; stagnant damp invites mildew
- Temperature
- 60–75 °F
- Mature size
- 12–18 in tall & wide
- Repotting
- Yearly in spring into a shallow, wide pot
- Propagation
- Leaf cuttings: even a wedge of leaf on moist mix sprouts plantlets; rhizome division.
When something looks wrong
- Overwatering signs
- Mushy stems, collapsing rhizome, yellowing leaves in wet soil
- Underwatering signs
- Limp, drooping leaves with dry crispy edges
- Common pests
- Mealybugs, spider mites, thrips; powdery mildew is the real enemy
Common problems 🩺
The usual suspects when Rex Begonia looks unhappy. Most houseplant trouble is watering or light, not disease — see all plant problems if you are not sure which plant is the culprit.
White powdery patches on the leaves
Likely cause
Powdery mildew — the classic rex begonia problem, caused by wet leaves and stagnant air.
What to do
Never mist. Water the soil only, improve airflow, and remove affected leaves.
Thinning out and losing leaves in winter
Likely cause
Many rex cultivars go semi-dormant in midwinter.
What to do
Water sparingly and wait. It rebuilds from the rhizome in spring — do not throw it out.
Mushy rhizome and collapsing stems
Likely cause
Overwatering. The rhizome rots fast.
What to do
Water only when the top inch is dry, and use a light, airy mix in a shallow pot.
More like this 🌿
Have a rex begonia?
Track it in DueDrop, with watering every 9 days, feeding every 28 days, prefilled for you.
Start tracking free