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Rex Begonia Indoor Care

Rex Begonia Indoors

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Rex Begonia Indoor Care Guide

This Rex Begonia indoor care guide covers all you need to know to better understand the Begonia species and how to care for Rex Begonia plants indoors.

Probably one of the most interesting looking plants due to their texture, hues, and shape, Begonias are named after a 17th-century French plant enthusiast called Michael Begon.

A beautiful tropical plant, the Begonia has more than 900 species under its wing. Besides the original species, the plant also has countless mutations and hybrids.

Asymmetrical leaves are one of the key features of Begonia. Of course, the leaf sizes vary according to the species you decide to go for. The stem is usually plump and falls into either the male or female category.

If you want flowers, I suggest you go for the female variety as its flowers have a longer life than those of their male counterparts. The leaves come in a range of different shapes from round leaves with edgy perimeters to stretched hearts.

There are three kinds of Begonia plants that make the most popular choices as indoor plants.  Each variety is special because of unique characteristics; however, they’re all quite similar in their care requirements. These plants include Winter-blooming Begonias, Angel-wing Begonias and my personal favorite, Rex Begonias.

Although this article focusses on how to care for Rex Begonia plants, you could safely apply my recommendations to all three varieties, as they all thrive in a shaded, humid environment with rich textured, aerated soil. Making sure that the soil is never over-watered, is probably the most important thing to keep in mind when caring for Rex Begonias.

How To Care for Rex Begonia Plants

Rex Begonias are known for their longevity and make an absolutely beautiful addition to your houseplants since they sprout flowers that are so pleasing to the eye. It’s also easy to propagate them compared with other varieties, a really nice thing to know if you are a beginner.

Rex Begonia indoor care does require a little more TLC than the other two varieties. But they are one of the most beautiful species of Begonias with colorful, patterned and interesting shaped leaves. They grow best in organically rich soil and humid, tropical environment with shade.


Since they tend to do well in shaded areas, the light they require should also be temperate. If you’re growing this variety indoors, they’re best kept under fluorescent lights or near a window located, east-side.

In winter, they should be moved to a west or south window. If the plant produces flowers, additional light will help it thrive further during colder months.


Rex Begonias are tropical plants; hence warmth is important for their survival. Make sure it doesn’t get too cold for your plant and the temperature doesn’t fall below 13C/55F.

Water and Humidity

A moderately moist environment and soil works well for Rex Begonias. Be careful when watering, making sure you don’t overwater it.

A good tip would be to let the top inch of the soil dry out before watering them again. The plant requires high humidity but moderate humidity will also work for it.

Don’t worry about misting the plant as it can cause powdery mildew on the leaves. If you want to increase the humidity surrounding the plant, place it on a wet tray of pebbles. Of course, the roots should be placed on the wet pebbles and not submerged in water, otherwise, it may die.


A quick-draining, aerated soil should be used for Rex Begonia. This will not only prevent over-watering but also prevent any possible root decay.

The texture should also be light as heavy soil dries out more quickly. African violet soil is very suitable for use when planting a Rex Begonia, hence the two plants make good roommates.

Fertilizing Rex Begonias

Feeding the plant will increase its life but make sure you use only half or one-fourth strength dilution of the fertilizer. It should also be fed every two weeks from early spring to summer. I don’t recommend you feed your Begonia in winter.


Begonias also differ amongst themselves based on their root types. A Rex Begonia has thick rhizome roots that spread against the soil surface, therefore, you should use a pot which is shallow and wide.

When you’re repotting, make sure the container is not too large. Large containers can make the plant more susceptible to overwatering. Also, make sure the soil in the pot is arranged in a way that it gets enough air circulation to thrive.

Rex Begonia Propagation

Make use of stem cuttings to propagate Rex Begonias. These plants can also be propagated from leaf cuttings in a mixture of perlite and moist peat moss.

Some varieties of this plant can also be propagated from seed, however, if your Begonia is a hybrid you should use stem and leaf cuttings to grow it.  

Other Tips

Begonias don’t respond well to new environments so when you’re bringing a new one to your home or office, make sure it gets extra care. Also, when you’re purchasing this variety, make sure you use a local supplier. If local suppliers of Rex Begonias are not present in your area, go for a small plant when getting it shipped.

After getting the plant, enclose it in an airy plastic bag to prevent it from getting dry and limit its exposure to draughts.

Rex Begonia: Indoor Troubleshooting 

Problem: Yellow or wilted leaves.

Cause: The plant is overwatered.

Solution: Make sure the plant is not potted in a big container. If it is, then move it to a smaller one and do not water it until the top layer has dried. Also, the temperature should be warmer as cool temperatures contribute to the condition and worsen it.


Problem: Discoloration on the surface of leaves.

Cause: Fungal condition called Botrytis.

Solution: Prune leaves which are diseased and propagate the plant using the healthier stem tips. The fungus is prevalent in plants with rooted cuttings and can be avoided by using a rooting medium which is unsoiled and pathogen-free.


Problem: Dark spots with yellow borders.

Cause: Bacterial leaf spot.

Solution: Infested leaves should be removed to stop further spread of the bacteria and air circulation should be improved. If you own a Winter-blooming Begonia, I’d recommend you get rid of the plant itself as the disease would exist throughout the body.


Problem: Deformed flowers.

Cause: Mites or Thrips.

Solution: If you detect thrips, remove them physically from the infested parts of the plant. In case your plant is infested with mites, the problem you’re facing may be a bit more difficult to handle.

If there is an absence of thrips and yet the flowers are deformed, your plant is probably infested with mites. In such case, get rid of the infested plant.


Problem: White, dusty spots similar in appearance to flour.

Cause: Powdery mildew, a fungus that takes away the nutrients of your plant.

Solution: Infected leaves should be removed from the plant and make sure it receives more air. New leaves are less likely to get affected by the disease than older leaves so make sure you propagate new plants on an annual basis.


Problem: White cotton-like insects present on stems and leaves.

Cause: Mealybugs

Solution: The bugs should be removed physically with a cloth or cotton swab dipped in alcohol. You should also ideally isolate the plant so that the mealybugs don’t migrate to other plants and infest them. There is no need to use oil sprays to prevent pest or mealybug infestation.


Problem: Brittle and pale leaves.

Cause: Lack of shade and humidity

Solution:  Move your plant to a spot where light is moderate and there is adequate shade. The humidity should also be increased.


I hope that this article has helped you learn more about Rex Begonia indoor care

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How to care for indoor begonia plants

Christine Mattner

What started out as purely a desire to keep my indoor plants alive has turned into a full-blown passion for sharing what I have learned over the years about selecting, growing and caring for indoor plants with those who may be new to the wonderful world of houseplants.

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