Rex Begonia Care Guide
Rex Begonia
Begonia rex hybrids
Rex Begonias are grown primarily for their dramatic foliage rather than their flowers. “Magic Colors” plants may have leaves patterned with combinations of green, silver, burgundy, pink, purple or red, but they share the same basic care requirements.
Quick Care
Light: Bright, indirect light
Water: Water when the top ½–1 inch begins drying
Humidity: High, with good air circulation
Temperature: Approximately 65–80°F
Difficulty: Moderate to challenging
Pet friendly: No
Growth habit: Compact and rhizomatous
Light
Provide bright, indirect or filtered light. Strong indirect light helps maintain the plant’s vivid leaf colors.
Avoid intense direct sunlight, which can fade or scorch the foliage. Insufficient light may cause weak growth and duller coloring.
An east-facing window or a position near a filtered south- or west-facing window usually works well.
Water
Water when the top ½–1 inch of potting mix begins to feel dry. Saturate the soil thoroughly and allow all excess water to drain.
Avoid keeping the soil constantly wet. Rex Begonias have fleshy rhizomes that are susceptible to rot in saturated conditions.
Water the soil rather than pouring water over the leaves or crown. Reduce watering slightly during winter or periods of slower growth, but do not allow the root ball to dry completely.
Temperature and Humidity
Maintain temperatures between approximately 65°F and 80°F. Protect the plant from cold drafts, sudden temperature changes and temperatures below 55°F.
Rex Begonias prefer high humidity—often considerably higher than the average heated home. A humidifier, greenhouse cabinet or naturally humid room can help.
High humidity must be paired with air circulation. Constantly wet leaves and stagnant air encourage fungal and bacterial problems.
Avoid routine misting, which can leave moisture sitting on the textured foliage.
Soil and Repotting
Use a loose, moisture-retentive but well-draining potting mix rich in organic matter. Perlite and fine orchid bark can improve drainage and airflow.
Rex Begonias have shallow, spreading root systems. A moderately shallow pot is often more appropriate than a deep container.
Repot when the rhizomes and roots have filled the container or the soil has become compacted. Choose a new pot only slightly larger than the existing one.
Fertilizing
Apply a balanced liquid houseplant fertilizer at approximately one-quarter to one-half strength every four to six weeks during active spring and summer growth.
Reduce or stop feeding during fall and winter. Excess fertilizer can burn the delicate roots and cause brown leaf edges.
Pruning and Propagation
Remove yellow, damaged or diseased leaves with clean scissors.
Rex Begonias can be propagated from leaf cuttings, sections of healthy leaves or by dividing the rhizomes during repotting.
Keep propagation media moist but not saturated and provide warmth, humidity and bright indirect light.
Flowering
Small flowers may appear above the foliage. They are normal but are usually less showy than the leaves.
Flower stems can be left in place or removed if you want the plant to direct more energy toward foliage production.
Common Problems
Crispy brown edges: Often caused by low humidity, dry soil, mineral-heavy water or excess fertilizer.
Soft leaves or rhizomes: Usually associated with overwatering or rot.
Powdery or spotted foliage: May indicate fungal disease encouraged by wet leaves and poor air circulation.
Faded colors: Often caused by too much direct sun or insufficient indirect light.
Drooping with dry soil: The plant likely needs water.
Drooping with wet soil: Possible root or rhizome damage.
Fine webbing, white cottony material or distorted new growth: Inspect for spider mites, mealybugs or thrips.
Pet Safety
Rex Begonias are not considered pet-safe. They contain soluble calcium oxalates that can cause vomiting and excessive salivation when ingested. The underground portions are considered the most toxic.
Keep the plant out of reach and contact a veterinarian or pet-poison service if it is eaten. ASPCA Rex Begonia profile
Mary Mae’s Best Advice
Rex Begonias want high humidity but do not want wet leaves or soggy soil. Use a humidifier instead of frequent misting, provide some air circulation and water only when the soil surface begins drying.
