Rex Begonia

Overview

Rex Begonias (Begonia rex-cultorum), often called Painted-Leaf Begonias or King Begonias, are a stunning group of rhizomatous begonias prized for their extraordinarily colorful and intricately patterned foliage. Native to the forests of eastern Asia, particularly regions of India, China, and Vietnam, these plants have been extensively hybridized to create hundreds of cultivars with an astonishing array of colors, patterns, and textures.

The most captivating feature of Rex Begonias is undoubtedly their leaves. Large, asymmetrical foliage displays dramatic combinations of silver, pink, purple, red, green, and metallic hues arranged in zones, spirals, splashes, or bands. Leaf textures range from smooth and glossy to deeply textured with pronounced veining. The undersides of the leaves often display rich burgundy or red coloration, adding another dimension to their ornamental value.

Rex Begonias grow from rhizomes—horizontal stems that grow just at or below the soil surface—rather than from traditional root systems. This growth habit influences their care requirements and propagation methods. They typically form compact mounds 12-24 inches tall and wide, with new leaves unfurling dramatically as they emerge.

While Rex Begonias can produce small, insignificant pink or white flowers, they're grown almost exclusively for their spectacular foliage. Many growers actually remove flower buds to redirect the plant's energy into maintaining its vibrant leaf coloration and form.

As tropical understory plants, Rex Begonias prefer conditions that mimic their natural habitat: bright indirect light, high humidity, and consistently moist (but not soggy) soil. While they require more specific care than some houseplants, their extraordinary beauty makes them worth the extra attention for many plant enthusiasts.

With their jewel-like colors and patterns, Rex Begonias make stunning focal points in houseplant collections and add a touch of exotic elegance to indoor spaces. Their moderate size makes them perfect for tabletops, plant stands, or terrariums where their intricate leaf patterns can be appreciated up close.

Care Guide

Light Requirements

Rex Begonias need adequate light to maintain their vibrant coloration, but must be protected from direct sunlight:

• Bright indirect light: Ideal for maintaining vibrant leaf patterns and colors
• Medium light: Will survive but may develop less intense coloration
• Low light: Not recommended as it leads to faded colors and leggy growth
• Direct sunlight: Avoid as it can scorch the delicate leaves and fade colors

For optimal growth and the most vibrant leaf patterns, place your Rex Begonia near an east or north-facing window where it will receive bright, filtered light throughout the day. If placed near a south or west-facing window, ensure the plant is positioned several feet away from the window or protected by a sheer curtain to filter the intense direct sunlight.

The light requirements of Rex Begonias directly affect the vibrancy of their distinctive coloration. Insufficient light causes colors to fade and patterns to become less pronounced, while too much direct light can burn the leaves and bleach the colors. Finding the right balance is key to maintaining the plant's ornamental value.

During winter months when light levels naturally decrease, you may need to relocate your Rex Begonia to the brightest spot available in your home. If adequate natural light is unavailable, supplemental grow lights can help maintain healthy growth and vibrant coloration during darker months.

Watering

Proper watering is crucial for Rex Begonias, as they prefer consistently moist soil without becoming waterlogged:

Watering Schedule:

• Keep soil consistently moist but not soggy
• Typically water when the top half-inch of soil feels dry to the touch
• Usually requires watering every 5-7 days, depending on your home's conditions
• Reduce frequency slightly in winter when growth slows
• Increase during hot, dry periods when soil dries more quickly

Watering Technique:

• Water at the soil level, avoiding wetting the leaves whenever possible
• If leaves get wet, gently pat them dry to prevent fungal issues
• Water thoroughly until it flows from the drainage holes
• Empty the saucer to prevent the plant from sitting in water
• Use room temperature water to avoid shocking the roots

Water Quality:

• Rex Begonias can be sensitive to chemicals in tap water
• If possible, use rainwater, distilled water, or filtered water
• If using tap water, let it sit out overnight to allow chlorine to dissipate

Rex Begonias communicate their watering needs through their leaves. Drooping or wilting indicates underwatering, while yellowing leaves often signal overwatering. The plant prefers consistent moisture but is susceptible to root rot if kept too wet.

Finding the right watering balance can be one of the trickier aspects of Rex Begonia care. When in doubt, it's generally better to err slightly on the drier side than to overwater, as these plants can recover more easily from slight underwatering than from root rot caused by overwatering.

Soil

Rex Begonias thrive in light, well-draining soil that retains some moisture:

Ideal Soil Mix:

• 2 parts African violet potting mix
• 1 part perlite or pumice
• 1 part coco coir or peat moss
• Optional: Add a small handful of orchid bark for additional aeration

This combination creates a light, airy mix that holds moisture while still allowing excess water to drain away quickly. The addition of perlite or pumice helps create air pockets in the soil, promoting healthy root development and preventing compaction.

Container Considerations:

• Always use pots with drainage holes
• Shallow pots work well as Rex Begonias have shallow root systems
• Plastic or glazed ceramic pots retain moisture better than terracotta
• Consider the mature size when selecting a container—most Rex Begonias stay relatively compact

Repot your Rex Begonia every 1-2 years, or when it has clearly outgrown its container. The best time to repot is in spring during the active growing season. When repotting, handle the plant gently to avoid damaging the rhizomes and position it at the same depth it was previously growing.

These plants actually prefer to be somewhat root-bound, so don't rush to repot them into much larger containers. When repotting, choose a pot that's only 1-2 inches larger in diameter than the current one.

Temperature & Humidity

As tropical plants, Rex Begonias have specific temperature and humidity preferences:

Temperature:

• Ideal range: 65-75°F (18-24°C)
• Minimum temperature: 60°F (15°C)
• Will suffer damage below 55°F (13°C)
• Avoid sudden temperature fluctuations
• Keep away from cold drafts, heating vents, and air conditioners

Humidity:

• Prefers high humidity (50-70%)
• Will struggle in dry environments below 40% humidity
• Increase humidity through these methods:
  • Use a humidifier near the plant (most effective method)
  • Place on a humidity tray (pebble tray with water)
  • Group with other plants to create a microclimate
  • Grow in a terrarium or under a glass cloche for naturally higher humidity
  • Place in naturally humid rooms like bathrooms (if adequate light is available)

Humidity is absolutely crucial for Rex Begonias. In low humidity, leaves may develop brown edges and tips, growth will slow, and the plant becomes more susceptible to pest infestations, particularly spider mites. If you notice these signs, take immediate steps to increase humidity around your plant.

While Rex Begonias can adapt to normal household temperatures, they're sensitive to cold drafts and sudden temperature changes. During winter, be especially mindful of keeping them away from cold windows and doors. Similarly, avoid placing them near heating vents, which can create hot, dry conditions that stress these humidity-loving plants.

Fertilizing

Rex Begonias benefit from regular but moderate fertilization to support healthy growth and vibrant coloration:

Fertilizing Schedule:

• Apply a balanced, water-soluble houseplant fertilizer diluted to half the recommended strength
• Fertilize once a month during spring and summer (active growth period)
• Reduce to once every 2-3 months in fall
• Do not fertilize in winter when growth naturally slows
• Resume regular fertilizing in spring when new growth appears

Fertilizing Tips:

• Use a balanced formula (such as 10-10-10) or one specifically formulated for foliage plants
• Liquid fertilizers are easier to control and less likely to cause fertilizer burn
• Always apply fertilizer to moist soil to prevent root burn
• Flush the soil thoroughly with water every few months to prevent salt buildup

Rex Begonias are moderate feeders and can be sensitive to over-fertilization, which can cause leaf burn, brown leaf tips, or salt buildup in the soil. Signs of over-fertilization include brown or black spots on leaves, especially near the edges, and a white crust on the soil surface.

Under-fertilization typically manifests as smaller leaves, less vibrant coloration, and slower growth. Finding the right balance of nutrients is important for maintaining the plant's ornamental value and supporting healthy growth.

Propagation

Rex Begonias can be propagated through several methods, with leaf cuttings being the most popular:

Leaf Wedge Method:

1. Select a healthy, mature leaf with well-defined veins
2. Using clean, sharp scissors, cut the leaf into wedge-shaped sections, each containing a main vein
3. Place the wedges vein-side down on a tray of moist propagation mix (equal parts perlite and peat moss works well)
4. Press gently to ensure good contact between the vein and the soil
5. Cover with a clear plastic dome or bag to maintain high humidity
6. Place in bright, indirect light (avoid direct sun)
7. Keep soil consistently moist but not soggy
8. New plantlets will emerge from the cut edges in 3-6 weeks
9. Once plantlets have several leaves and are about 2 inches tall, carefully separate and pot individually

Whole Leaf Method:

1. Select a healthy, mature leaf with stem attached
2. Using a clean, sharp knife, make small incisions across the main veins on the underside of the leaf
3. Lay the leaf top-side up on moist propagation mix
4. Secure the leaf to the soil with U-shaped pins or small weights to ensure good contact
5. Cover with a clear plastic dome or bag to maintain high humidity
6. Follow the same care instructions as for the wedge method
7. New plantlets will emerge from the incisions in 3-6 weeks
8. Once plantlets have several leaves, carefully separate and pot individually

Rhizome Division:

1. Division is best done during repotting in spring
2. Remove the plant from its pot and gently shake off excess soil
3. Look for natural divisions in the rhizome or carefully cut the rhizome into sections, ensuring each section has both growing points and roots
4. Plant each division in its own pot with fresh soil mix
5. Water thoroughly and place in bright, indirect light
6. Keep soil consistently moist and humidity high during the establishment period
7. Avoid fertilizing for at least a month after division

Important Propagation Tips:

• The best time to propagate is during spring or summer when growth is most active
• Maintain high humidity around new cuttings or divisions
• Avoid direct sunlight, which can stress new plants
• Be patient—while plantlets may develop relatively quickly, it can take several months for new plants to establish and begin active growth
• Expect some variation in leaf patterns and colors in propagated plants

Propagation is an excellent way to expand your Rex Begonia collection or share these beautiful plants with friends. The ability to create multiple new plants from a single leaf is one of the most rewarding aspects of growing Rex Begonias.

Common Problems

While Rex Begonias are generally resilient when their humidity and watering needs are met, they can experience several common issues:

Brown Leaf Edges and Tips:

• Cause: Low humidity, underwatering, or fertilizer buildup
• Solution: Increase humidity, adjust watering schedule, and flush soil occasionally to remove mineral buildup

Yellowing Leaves:

• Cause: Overwatering is the most common cause, though normal aging of older leaves also produces yellowing
• Solution: Reduce watering frequency, ensure proper drainage, and remove only completely yellow leaves

Fading Leaf Colors:

• Cause: Insufficient light or aging leaves
• Solution: Move to a brighter location (still avoiding direct sun)

Leggy Growth:

• Cause: Insufficient light causing the plant to stretch toward light sources
• Solution: Move to a brighter location (still avoiding harsh direct sun)

Powdery Mildew:

• Cause: Fungal infection, often from poor air circulation combined with high humidity
• Symptoms: White, powdery coating on leaves
• Solution: Improve air circulation, avoid wetting leaves, and treat with appropriate fungicide if necessary

Pests:

• Spider Mites: Tiny pests that cause stippling on leaves and fine webbing, particularly in dry conditions
• Mealybugs: White, cotton-like clusters in leaf joints and on stems
• Aphids: Small insects that cluster on new growth and undersides of leaves
• Solution: Increase humidity (for spider mites), wipe leaves with insecticidal soap or neem oil, isolate affected plants

Root Rot:

• Cause: Overwatering, poor drainage, or compacted soil
• Symptoms: Wilting despite moist soil, yellowing leaves, mushy stems, foul smell
• Solution: Reduce watering, ensure proper drainage, and in severe cases, take healthy cuttings to propagate a new plant

Leaf Spot Diseases:

• Cause: Fungal or bacterial infection, often from water on leaves in cool conditions
• Symptoms: Brown or black spots on leaves, sometimes with yellow halos
• Solution: Avoid wetting leaves, improve air circulation, remove affected leaves, and treat with appropriate fungicide if necessary

Most Rex Begonia problems can be prevented with proper care focused on appropriate light, consistent moisture without overwatering, and adequate humidity. Regular inspection helps catch issues early when they're easier to address.

Popular Varieties

The Rex Begonia group includes hundreds of cultivars with an incredible diversity of colors, patterns, and textures. Here are some of the most popular and distinctive varieties:

'Escargot'

• Distinctive spiral pattern resembling a snail shell
• Green leaves with silver banding following the spiral
• Highly textured surface with deep veining
• One of the most recognizable and sought-after varieties
• Moderate growth rate

'Fireworks'

• Deeply lobed, star-shaped leaves
• Silvery centers with dark green edges
• Red veining throughout
• Dramatic, eye-catching appearance
• Compact growth habit

'Red Kiss'

• Deep burgundy to almost black leaves
• Bright pink to red spots and splashes
• Metallic sheen to the foliage
• Rich, dramatic coloration
• Medium-sized leaves

'Silver Queen'

• Predominantly silver leaves with green edges
• Subtle pink undertones
• Elegant, refined appearance
• Classic variety that's been popular for decades
• Relatively easy to grow

'Merry Christmas'

• Red and green coloration reminiscent of holiday colors
• Deeply textured, crinkled leaves
• Star-shaped leaf form
• Festive appearance year-round
• Medium to large leaves

'Malachite'

• Emerald green leaves with black edges
• Metallic, shimmering quality to the foliage
• Relatively smooth leaf texture
• Named after the mineral it resembles
• Striking contrast between colors

'Raspberry Swirl'

• Swirling patterns of pink, silver, and green
• Raspberry-red undersides to the leaves
• Medium-sized, slightly pointed leaves
• Vibrant, cheerful coloration
• Moderate growth rate

'Harmony's Red Robin'

• Predominantly red leaves with silver highlights
• Deeply textured surface
• Ruffled leaf edges
• Compact growth habit
• Dramatic coloration

'Shadow King' Series

• Various cultivars with different color patterns
• Bred specifically for better tolerance to lower humidity
• More forgiving of average home conditions
• Excellent choice for beginners
• Includes several color variations

'Jurassic' Series

• Modern series with extra-large leaves
• Various color patterns available
• Thicker, more substantial leaves than many varieties
• Bred for improved home tolerance
• Statement plants due to their size

'Benitochiba'

• Deep green leaves with red centers
• Star-shaped leaf form
• Red hairs on stems and leaf edges
• Distinctive textured appearance
• Medium to large size

'Iron Cross'

• Dark green leaves with a distinctive cross-shaped chocolate brown pattern in the center
• Relatively smooth leaf texture
• Smaller leaves than many Rex varieties
• Unique and instantly recognizable pattern
• Compact growth habit

These diverse Rex Begonia varieties offer something for every plant enthusiast, from beginners to advanced collectors. While they share similar care requirements, the different leaf forms, colors, and patterns create distinctly different visual effects, allowing for creative combinations in plantings and displays.

With their jewel-like colors, intricate patterns, and relatively compact size, Rex Begonias make excellent houseplants for those willing to provide the higher humidity and consistent care they require. Their extraordinary beauty makes them perfect statement plants for tabletops, plant stands, or anywhere their detailed patterns can be appreciated up close.