Rex Begonia Plant: Complete Care and Growing Guide

Did you know that rex begonia is considered perennial in tropical and semitropical regions but grown annually in North America? Although rex begonias have exquisite flowers, they are more commonly planted for their vibrantly colored and intriguingly textured leaves.

Dark leaves with pronounced silvery grey stripes distinguished these plants. They are begonias with rhizomatous roots. A rhizome is a thickened stem that produces leaves. Want to have another breathtaking indoor houseplant? Read more below to learn more about rex begonia care tips.

rex begonia care card

More About Rex Begonias

The begonia rex is also known as the painted-leaf begonia or the fancy-leaf begonia. It has beautiful variegated leaves in bright green, silver, purple, or red. You typically grow them as an outdoor container plant or as houseplants.

Still, finding the right conditions for growing rex begonia to display the leaf color can be challenging. While light is not an issue, temperatures can be. Hence, daytime temperatures for the rex begonias to thrive need to be around 70°F while the nighttime temperatures must be around 60°F.

For indoor plants, the humidity level needs to remain constant, around 50%—also, a warning: these plants are toxic to cats and dogs.

Begonia Rex Plant Care 

rex begonia plant

When caring for the rex begonia plant, we have a short list here before we get into each in more detail.

  • Use a porous potting mix in a shallow pot for your rex begonia plant.

  • When planting outdoors, we recommend doing this after the frost passes. But you can plant them indoors at any time.

  • Rex begonias, you can feed regularly, but keep your plant moist and avoid overwatering.

  • Provide these houseplants with a lot of bright indirect light but not direct sunlight.

  • Also, rotate your rex begonias frequently for even light distribution.

  • Lastly, pinch off the blooms to help keep a beautiful leaf display.

Ideal Soil 

A well-draining and slightly acidic potting mix is essential for begonia rex plants. A common choice for begonia rex is a peat-based mix. This mix provides good drainage and retains moisture without becoming overly soggy. Begonias appreciate consistent moisture but don’t like to sit in waterlogged soil.

Adding perlite or vermiculite to the mix to further improve drainage and aeration. These materials help prevent compacting of the potting soil and enhance root health. Sphagnum moss can also be a beneficial addition to the soil mix.

It aids in retaining moisture and maintaining humidity around the plant’s roots, which is especially helpful for begonia rex plants, as they prefer higher humidity levels. Begonia rex plants prefer slightly acidic soil with a pH between 5.5 and 6.5.

You can adjust the pH by adding materials like sphagnum peat moss if necessary. Including a small amount of well-rotted compost or organic matter in the potting mix can provide some nutrients for your plant. Just be cautious not to overdo it, as these plants are sensitive to excessive fertilization.

Commercial potting mixes are available specifically formulated for begonias or houseplants, which can be a convenient option.

Watering

Regular watering is vital for a begonia plant. Nonetheless, be careful not to overwater them. The painted leaf begonia should be watered throughout the summer and growing season.

Before watering, let the soil surface dry out. It is preferable to keep your plant on the drier side. But never leave them to dry out completely, as this will lead to your rex begonia’s death. It’s best not to get the leaves too wet, as this can lead to powdery mildew.

Your painted leaf may go dormant and drop its leaves in winter. Only give it a little water until new leaves emerge in the spring. Take note: check the soil first before watering. Overwatering is a kiss of death for the rex begonia and remember well-draining soil.

Lighting Needs

begonia lighting requirement

Bright indirect light is excellent for the painted leaf begonia. It must be shielded from summer heat and sunlight in more southern climates, but you can plant it outside all year. While some sun shouldn’t be an issue in more northern climates, take the plant indoors during the cooler months.

Some direct sunlight is good for brief periods, especially from an eastern window with milder morning sun. Yet, you may easily deflect direct sunlight with sheer curtains or place the plant a few feet away from a window with bright light.

The reason is that the foliage might be burned by too much direct sunlight. It may be placed indoors or outdoors, as long as you provide them with the proper light your rex begonia needs.

Rex Begonia Temperature 

Changes in temperatures below 60 degrees Fahrenheit are harmful to begonia rex. With that in mind, moderate temperatures such as 60 to 70 degrees Fahrenheit (15.5 to 21.1 degrees Celsius) are great for rex begonias. When temperatures drop below freezing, their growth slows down.

Some begonias lay dormant in the winter due to not receiving enough light.

Humidity 

Humidity appears to be an essential factor in achieving an optimal plant leaf size with these houseplants. The Begonia rex plants require high humidity (greater than 50%). That is why growing rex begonias indoors during the winter can be challenging.

Try to avoid dry air at all costs. Group them on a water-filled pebble tray if you’re growing in containers. This results in a humidified environment with less dry air. Also, avoid spraying the plant’s leaves. This can lead to spots due to uneven air circulation.

Also, remember these plants prefer moist soil but not too much water, as it can lead to root rot.

Rex Begonias Fertilizer

When your Begonia rex cultorum starts to grow in the spring, start fertilizing them. Add a quarter-strength or half-strength liquid fertilizer to your plants every two weeks. Please don’t feed your houseplants during the winter because they aren’t thriving.

Their roots won’t be able to absorb the nutrients and may suffer harm as a result.

Growth Zone

In tropical and semitropical settings, rex begonias are considered perennial. Rex begonias are understory plants that grow in their natural habitat under tree canopies in shaded to partially shady parts of jungles.

Frost is also a problem for rex begonias. USDA zones 10 and 11 are suitable for this kind of begonias. In North America’s zones 10 and 11, you can grow rex begonia as indoor plants.

Potting

Any pot or hanging basket will work, but ensure it has drainage holes at the bottom. Not providing free-draining soil with holes can lead to root rot. Rhizomatous plants, such as rex begonias, grow from a shallow, knobby rhizome.

As a result, they flourish in large shallow pots with plenty of room for the roots to develop. When the rhizome grows up against the pot’s sides, it’s time to repot it with new soil.

Pruning

Rex begonias need minimal pruning unless they have long, barren stems that need to be pruned back. Alternatively, if you want to create a fuller look, cut the stem down to the base with clean pruning snips, and the remaining section should produce new leaves and stems.

To keep the plant looking good, trim away any dead or rotting leaves. Pinching the tips of young outdoor plants also encourages them to become fuller.

Propagating Begonia Rex Cultorum

leaf cutting propagation

Leaf-cutting or rhizome division is an easy way to propagate begonias. And the rex begonia is one of those. You can do this by transplanting the plant in spring and winter, but it can take longer when cold.

Leaf Cutting Propagation:

  1. Choose a healthy and mature leaf from your Rex Begonia plant. Look for a leaf with no signs of disease or damage.

  2. Use a clean, sharp knife or scissors to make a clean cut. Ideally, cut the leaf into sections that are 2 to 4 inches long. Each section should have a vein running through it, as this is where new growth will emerge.

  3. Fill a small container or seed tray with well-draining potting soil. A mix that includes peat moss and perlite works well.

  4. Insert the cut end of each leaf section into the soil, burying it about half an inch to an inch deep. You can plant multiple sections in the same container, spacing them apart.

  5. Cover the container with a clear plastic lid or place it inside a plastic bag to create a mini greenhouse effect. This helps maintain high humidity, which is crucial for successful leaf-cutting propagation.

  6. Put the container in a location with bright, indirect light. Avoid direct sunlight, as it can scorch the cuttings.

  7. Keep the soil consistently moist but not soggy.

You should start seeing roots forming on the cuttings in a few weeks to months. This signifies that they are ready to be transplanted into individual pots. Gently remove the rooted cuttings from the container and plant them in their pots using the same growing media used for mature rex begonias.

Division Propagation:

  1. Choose a mature plant that has several stems and a well-developed root system. This is typically done during repotting.

  2. Carefully remove the entire plant from its pot. You may need to shake off excess soil to expose the root system gently.

  3. Divide the plant into sections using a clean, sharp knife or scissors. Each section should have a portion of the root system and at least one stem with leaves.

  4. Plant each divided section in its pot with fresh potting soil. Make a hole in the soil, place the section in it, and gently firm the soil around it.

  5. Water the newly potted divisions thoroughly and keep the soil consistently moist as they establish themselves.

  6. Place the potted divisions in a bright, indirect light location and provide them with the same care as mature rex begonia plants.

Rex Begonia Varieties and Similar Plants

Many attractive hybrid rex begonia variants exist. Unfortunately, some are frequently unlabeled or mislabeled. Here are the most stunning varieties of rex begonia you can grow in your garden, with asymmetrical foliage, vibrant colors, and patterns:

Begonia rex‘ Boston Cherries & Chocolate

This is a rex-type plant with dark purple leaves with medium spherical pink and silver dots. It’s a pretty simple rex to grow.

Begonia rex‘ Snow Queen’

This comes with striking silver-colored leaves. It’s also disease-resistant, which is the advantage of this plant.

Begonia rex ‘Escargot’

Is an evergreen, rhizomatous perennial known for its spiral-shaped foliage coiling around the leaf’s base. The spiraling green, silver, and chocolate colors highlight the snail curl design. That’s producing an eye-catching design.

Rex Begonia Diseases & Pests

rex begonia plants

Diseases and pests in your gardening are inevitable. That is why looking out for those is essential in your rex begonia care guide.

Pests

Rex begonias are subject to mealy insect infestations when the temperature inside is warm. Immerse a cotton ball or swab in alcohol and dab the mealybugs off the plant to manage an outbreak. You can also use alcohol to spritz the entire begonia. Just ensure not to get any on the soil.

Aphids and caterpillars can also be a concern. Most of the time, spraying the bugs with insecticidal soap will solve the problem. In addition, you can control the invasion of slugs and snails by using slug bait near your plants.

Diseases

Botrytis Leaf Blight

It affects the lowest leaves that come into touch with the soil, and it manifests itself as water-soaked, dark lesions that become larger over time. Prevent the situation by watering according to your schedule. Plus, avoid putting water on the leaves and water early in the day, so the foliage has time to dry before nightfall.

Powdery mildew

Happens when the soil is maintained excessively damp, and the foliage becomes soaked. A white powdery substance covering the leaves is a sign. Remove sick leaves, water properly, and avoid getting the foliage damp to control the problem.

Frequently Asked Questions

Rex Begonias are known for their stunning and intricate foliage. They are primarily grown for their unique leaf patterns and colors.

While they prefer bright yet indirect light, Rex Begonias can tolerate lower light conditions, but their growth may become slower, and the foliage may not be as vibrant.

Rex Begonias can produce small, inconspicuous flowers, but they are typically grown for their foliage, not their blooms. Some varieties may have more showy flowers.

Yes, Rex Begonias can be propagated from leaf cuttings. This is a popular method to create new plants with the same unique foliage patterns.

Rex Begonias thrive in temperatures between 65°F to 75°F (18°C to 24°C). Avoid exposing them to cold drafts or extreme temperature fluctuations.

Regularly inspect your plant for pests like spider mites, aphids, or mealybugs. If infestations occur, treat them with insecticidal soap or neem oil.

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