Rex begonia care guide
Begonia rex
Also known as: Painted-leaf begonia, King begonia
Pets and children
Considered toxic
Begonias contain oxalates, most in the rhizome and stems: dogs and cats that eat them can vomit, drool and have mouth pain, so keep it out of reach and contact a veterinarian (or a doctor, for a child) if eaten.
How often to water Rex begonia
- Spring–Summer (Mar–Sep)
- Every 4 days
- Once the topsoil is dry, water at the base without wetting the leaves, as a guide; constantly wet soil rots the rhizome.
- Autumn (Oct–Nov)
- Every 6 days
- Water about a day or two after the topsoil dries.
- Winter (Dec–Feb)
- Every 10 days
- Growth stops, so water sparingly about three to four days after the soil dries.
Light and placement for Rex begonia
Bright shade with no direct sun is generally right: strong light scorches the leaves, and too dim a spot dulls the colors and stretches the stems; give it airflow but keep it out of dry drafts.
Overwintering Rex begonia
Overwintering guide: 10°C (50°F) or above
Tender to cold: overwinter it indoors at about 10°C; heated air crisps the leaf edges, so raise the humidity around the pot, for example with a tray of water nearby, and expect fewer leaves until spring growth resumes.
Fertilizing and repotting Rex begonia
Fertilizer
Diluted liquid feed about every two weeks from April to June and again in September and October; none in midsummer or winter, when the plant is weak.
When to repot
Spring–Summer (Mar–Sep)
Common problems with Rex begonia
- Overwatering or wetting the leaves rots the rhizome and foliage.
- Dry heated air browns and crisps the leaf edges.
- Summer heat with poor airflow brings powdery mildew.
Tips for growing Rex begonia
- The rhizome creeps sideways, so a wide, shallow pot suits it better than a deep one.
- A leaf laid on moist soil sprouts plantlets from the cut veins.
- Raising the humidity around the plant works better than misting the leaves, which invites disease.
These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.
Keep your plant log going
Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.
