Everything You Need to Know About Caring for a Rex Begonia

A Rex Begonia, whose scientific name is begonia rex-cultorum, is a beautiful plant that features variegated leaves in a wide array of colors. There are over 500 different varieties of this plant, each featuring slightly different leaves.

Some have spotted leaves, some have leaves that are a deep red, purple, green or even yellow. These plants are planted almost exclusively so their beautiful leaves can be admired.

In fact, their leaves are so beautiful that the plant is often referred to as painted-leaf begonias or fancy-leaf begonias. If you are looking for an indoor plant or a potted plant to put on a balcony or patio, the rex begonia may be a great option for you.

Learning how to care for your rex begonia can help it to last for multiple years. Read on to learn everything you need to know about caring for a rex begonia. 

How to Care for a Rex Begonia

The Rex Begonia is a plant that is often a houseplant or a container plant. If you are looking to add a little color inside of your home or want to dress up an apartment balcony or small patio area, this type of plant may be perfect for you.

However, before you go about purchasing any plant, it is important that you do a little bit of research and find out how to properly care for the plant.

This not only ensures that your growing conditions are ideal for the plant, but it also helps to ensure that you know how to give the plant the care it needs in order to thrive. 

begonia rex care
Rex Begonia in Pot

When it comes to the Rex Begonia, the plant is best known for its beautiful and colorful leaves that can reach up to six inches in length. However, the size, variations and color on the leaves are at its best when the plant is properly cared for.

As such, you should follow these tips to help your plant reach its full potential and look as beautiful as it possibly can. 

1. Sunlight

The Rex Begonia does well in bright indirect light. What this means is that the plant should be exposed to some light, but should not be exposed to direct sunlight. For example, you may want to place your indoor plant several feet away from a window.

The plant will get some light coming in from the window, but since it is not directly in the window, it will not receive too much sun. If you are placing a plant outside, you may want to place it in a partial shade area.

Sunlight Rex Begonia

If you are placing it in a spot where it does get some sunlight, try to place it in a spot that receives sun exposure either in the morning or the evening. Sun exposure in the middle of the day is too much for this plant and can lead to problems.

It is also important to rotate the plant. This helps to ensure that all of the plant is exposed to light regularly. 

2. Water 

The Rex Begonia plant prefers to grow in moist soil. However, this plant is also prone to root rot, which means that you cannot leave the plant sitting in soaked soil. The best way to water this plant is to feel the soil itself to determine if watering is needed.

If the top inch of soil is drying out, it is time to water the plant. If the top inch of soil is still damp to the touch, the plant has enough moisture at this time.

Watering Rex Begonia

Most people find that they need to water their Rex Begnoia plant about once a week. It is also important that you plant the plant in a pot that drains water, as this prevents water from sitting at the roots of the plant. 

3. Temperature

The Rex Begonia does best if it is planted in a hardiness zone of 10 to 12. The plant does well indoors if the temperature in your home is about 65 to 75 degrees. As a general rule of thumb, if you are comfortable inside your home, this plant is as well.

If you are cold or hot, so is the plant. If you are placing the plant outside, you should wait until temperatures are around 60 to 70 degrees.

Temperature Rex Begonia

You should bring the plant indoors when temperatures get much hotter or much colder than this. You may notice that the leaves of the plant may stop growing if temperatures get too hot or too cold for this plant. 

4. Humidity

One of the more unique aspects of the Rex Begonia is that it loves humid environments. The plant is a tropical plant, which explains why it thrives in humidity.

In a perfect world, the plant would love to keep in an environment where there is about 50 percent humidity.

Humidity Rex Begonia

However, the plant may still thrive with slightly more or significantly less humidity. Some hybrid versions can thrive in dry conditions. It is important to note that some people try to make-up for a lack of humidity by misting the plant or spraying it with a spray bottle.

That is not a great idea with this plant, as it can lead to the leaves being overwatered or fungus or mildew growth. If you need to increase the humidity in your home for this plant, the best option is to use a humidifier or place them in a bathroom when you take a steamy shower. 

5. Soil

Planting your Rex Begonia in the right soil can help your plant to thrive and increase its lifespan. As a general rule of thumb, the Rex Begonia prefers light and airy soils.

Soil Rex Begonia

Light and airy soils allow excess water to pass through the soil, which prevents root rot.

You should always avoid heavy potting soils with this type of plant, as they retain moisture, which can be devastating to this plant. Potting mixes that are designed specifically for African Violets are a great choice for the Rex Begonia. 

Planting Rex Begonias in Pots

The Rex Begnonia is a rhizomatous plant. This means that instead of a traditional root system, the plant has a rhizome. A rhizome is an underground stem or rootstalk.

In the case of the Rex Begnonia, the rhizome is very shallow and knobby.

As such, when you are looking to plant this plant in a pot, you should be looking for fairly shallow, yet wide pots. The rootstalk grows horizontally, rather than vertically.

Rex Begonias in Pots

Most Rex Begonias can grow to be about 18 to 24 inches wide, so you want a pot that can accommodate that. It is important to note though, that some hybrid varieties of this plant can grow larger, so always research the size of the specific plant you are getting to find the right type of pot for the plant. 

In addition to selecting a shallow, yet wide pot to plant your Rex Begonias in, you should also ensure that you are selecting pots that can drain.

Once again, root rot is a real concern with this plant. If water cannot drain from a pot, you can almost guarantee that wet roots will become an issue and your plant will fail to thrive or can die.

Ensuring you select a pot that can drain helps to keep soil at the proper level and ensures water can escape instead of saturating the rhizome root system. 

Common Problems Rex Begonias Can Experience

One of the great things about the Rex Begonia plant is that the plant will often give you signs that something is not quite right. This allows you to make changes for the plant to help it thrive.

This is a very durable plant that does not die easily.

Unfortunately though, many plant owners do not realize what these signs mean, and as such, they cannot correct the problem and give the plant the care it needs.

Here are a few common problems that you can experience with Rex Begonias, and what each of these problems may mean for your plant. 

1. Leaf Loss or Leaf Rot

Rex Begonias Leaf

If it looks like the leaves on your plant are falling off or starting to rot, your plant is likely over-watered. Start by ensuring that water is draining from the pot after it is watered. If the pot is draining, then consider waiting a few extra days before watering your plant.

For example, if you were watering your plant once a week, start watering it every ten days. It may take a month or two to see changes if you have been over-watering the plant. 

2. Wilting or Curling Leaves

Another problem that you may experience with the Rex Begonia is wilting or curling leaves. This is a sign that your plant is not receiving the care it needs.

Unfortunately, there are many reasons why your plant may have leaves that are wilting or curling.

Wilting or Curling Leaves Rex Begonias

If your plant needs more light, if the humidity levels are too low, or if your plant is not getting enough water, the leaves may begin to curl up or wilt. You may have to troubleshoot and make changes to identify the reason why your plant may not be thriving and what the exact problem may be. 

3. Overly Soft Leaves

Soft Leaves Rex Begonia

If the leaves on your Rex Begonia are overly soft, they may look floppy instead of firm. The reason why your leaves may be soft is because the plant is not getting the water it needs. If the leaves are overly soft, you may want to check the soil and ensure it is still slightly damp or moist.

You may need to increase the frequency in which you water your plant, and/or you may need to move the plant out of sunlight, which may dry the soil out. 

4. Powdery Patches on the Leaves

If you notice powdery patches on the leaves, your plant may be affected by either powdery mildew or botrytis fungal disease. A systemic fungicide can help to remove both the mildew or fungus.

Rex Begonia

When it comes to powdery mildew or fungus, the best course of action is to take action to minimize either of these issues.

The best way to prevent mildew or fungus is to remove dead leaves from the plant quickly and ensure there is good air circulation around the plant. Dead leaves and poor air circulation allow fungus and mildew to thrive and grow. 

5. Spots on the Leaves

Another issue that the Rex Begonia is susceptible to is bacterial leaf spot disease. This disease causes spots to appear on your plant leaves when spots should not be there. It is important to note that some hybrid Rex Begonias do have spots on the leaves.

As such, you need to be aware if spots should be present on your Rex Begonia or not.

Spots on the Leaves Rex Begonia

If there should not be spots, and you notice spots forming, you are likely dealing with this disease. This disease is caused by watering the leaves. You should never water the leaves on your rex begonia or spray water on them. If the leaves get wet, you can use a soft cloth to hand dry them.

Unfortunately, bacterial leaf spot disease is extremely difficult to remove, and as such, prevention is your best course of action. If you have leaves that are already affected, a copper fungicide may help.

If it doesn’t help, you may have to cut away all of the affected leaves to prevent the problem from spreading. 

6. Mealy Bugs

Finally, mealy bugs can be a problem with the Rex Begonia plant. One of the biggest misconceptions pertaining to indoor plants is that pests will not affect them.

This is not true, and mealy bug infestations can even move from one plant to another if the plants are close enough. If you notice fluffy blobs that are forming in the crooks or crevices of the leaves of your plant, you are likely seeing mealy bugs on the plant.

begonia rex care
Rex Begonia Leaf

If you notice the problem in just a couple spots, you can soak a q-tip or cotton swab in rubbing alcohol and lightly rub the alcohol over the affected area to kill the bugs. If the pests have taken over the plant, you may need to use an insecticidal soap or houseplant spray to kill the bugs.

The best way to prevent a mealy bug infestation on your Rex Begonia is to trim away dead growth and to not allow dead leaves to sit on the surface of the plant’s soil. 


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Other Things You Should Be Aware of With Rex Begonias

If you are a pet owner, you need to be aware that rex begonias are toxic to many animals, including dogs, cats and horses. The plant can cause kidney failure and vomiting. The most dangerous part of the plant is the root system.

However, leaves can also be poisonous if consumed, especially in smaller breeds of dogs and cats.

begonia rex care
Rex Begonia Bush

As such, this may not be the best plant to keep in your home if you have pets. If you love Rex Begonias and do have pets, always keep the plant out of the reach of your pet. If you have a pet and you suspect that your animal has grazed on the plant, you should call a vet immediately.

Do not wait until your pet exhibits signs or symptoms, as the poison is already affecting them at that point. 

There are hundreds of different hybrid versions of the rex begonia available, ensuring there is a plant that appeals to your needs. This plant features beautiful leaves, which have made it a favorite houseplant for plant lovers.

begonia rex care
Rex Begonia

And, while this plant does need some special care to grow and reach its full potential, it is fairly easy to care for. It is also a great plant for those who may not have a greenthumb or are just starting in the plant world as the plant will give you signs that it is not receiving the care it needs.

This allows you to make changes before the plant withers away or dies. Visit your local nursery today to inquire about rex begonias. 

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