Rex Begonia Plant – Care, Growing, Watering, Propagation

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Rex begonias (painted leaf begonias) may not be the easiest plant to grow indoors, but with the proper know-how, you’ll succeed in growing a thriving plant that will add liveliness and color to any indoor space.

Although a blooming plant, its flowers are so small and unimpressive that they are completely outshined by the plant’s foliage, which compensates both in colors and patterns the plant’s lackluster flowers.

Therefore, the rex begonia is a plant that will appeal to those who are more satisfied with elaborate foliage displays than blooms, especially that there are several rex begonia varieties.

Read my rex begonia plant care tips below and you too can enjoy the splendor of these plants.

Rex Begonia Plant Care Tips

Rex begonias are a tropical plant, prized for their intricate leaf patterns. They have a reputation of being difficult to grow, although there are varieties that are less demanding.

Follow my recommendations below and you’ll have an easier time growing these plants.

Plant Size

Because the leaves of rex begonias grow clumped together, the plant is dense looking and rounded. In height, painted leaf begonias can reach 12 to 24 inches, depending on the variety.

In width, they reach about the same size as their height.

You can create elaborate displays and combine different varieties, making sure each stay in their own pot. Clumping them together is not a good idea, since it can lead to diseases.

Light Requirements

Painted leaf begonias are high to medium light plants, so aim for bright indirect light all year round.

You can pick a west or east-facing window but avoid south-facing windows if the weather gets particularly hot in your area. You want to avoid direct sun exposure, which will certainly burn the leaves of the rex begonia.

Where there is a lack of natural light, artificial light in the form of fluorescent lighting can supplement the lack of natural lighting.

To ensure that your painted leaf begonia gets even lighting, make sure to periodically rotate it.

Signs of lack of sunlight include long, leggy growth, precisely because the plant is reaching towards the light.

In summer, you can move your rex begonia outdoors in partial shade if its light requirements are not properly met inside your home.

Watering

Rex begonias need thorough watering but should not be overwatered. Don’t water the leaves, only the soil to avoid fungal disease issues.

Slightly moist soil is ideal for painted leaf begonias, but excess moisture will cause root rot, so make sure the water drains properly from the pot and you empty the saucer of excess water.

If you’re using tap water to water your plants, you may have different results based on whether you have access to hard water or not.

High mineral salt content can cause leaf edge burn in rex begonias because of their inability to deal with the high loads of dissolved mineral salts present in hard water. Instead of tap water, you can use rainwater with excellent results.

Normally, you won’t need to water the plant more than once a week, but always let the soil guide you. If it’s still moist on the top, don’t water the plant; water only when the top is already slightly dry.

Temperature & Humidity

At the beginning of this article, I mentioned how rex begonias aren’t the easiest plant to grow. One of the chief issues with this plant is its preference for high humidity levels, something that not many of our homes can offer.

To meet the plant’s humidity requirements, you need to increase humidity levels either manually or by using a humidifier.

How do you know if your painted leaf begonia is getting enough humidity? Leaves will offer you a clue — leaves that have burnt edges indicate that the plant isn’t receiving the humidity it needs.

The ideal temperature for these plants is between 60°F to 85°F (15 °C to 30°C), which is the ideal range for most tropical plants.

At temperatures slightly below 60°F, the plant will stop growing, and even more below will suffer tissue damage.

Soil Type

The potting medium for rex begonias should have well-draining soil that is light and rich. Peat-based potting mixers are a good choice. Make sure the pot has drainage holes.

Fertilizing

Fertilizing can be beneficial for rex begonias especially if done right. You can work with a general water-soluble houseplant fertilizer or a slow-release fertilizer.

The all-purpose fertilizer should be used at quarter strength every two weeks during the growing season, while the slow release fertilizer should only be applied every three months.

With the use of fertilizers, there is a concern of salt build-up in the soil. This requires that you periodically (every 3-4 months) flush the soil to wash away any build-up.

Potting & Repotting

Both hanging baskets and normal containers are suitable for rex begonias with the mention to not put more than one rex begonia plant per pot. These plants grow densely, you should not crowd multiple plants together.

Rex begonias don’t mind being a bit root bound, but repotting each spring is beneficial to the plant.

Rex Begonia Plant Propagation

The easiest and most straightforward way to propagate rex begonias is by whole leaf cuttings. Simply put a leaf cutting in a mixture of moist peat moss and perlite and wait for it to root.

Different Types of Rex Begonia Plant

There are several rex begonia cultivars with some of the most popular ones being:

  • Escargot: This variety stands out through spiraling markings that are light green or silvery interposed on a dark green background. The spiraling leaves look like a snail.
  • Boston Cherries & Chocolate: This variety has dark purple leaves with pink or silver spots. It’s a less finicky variety that’s easier to grow.
  • Snow Queen: This rex begonia variety has beautiful silvery green leaves. The plant is known to have a high resistance to pests.
  • Fireworks: This variety certainly lives up to its name. The leaves offer a spectacular sight with silver leaves etched with a deep purple.

There are other hybrids and varieties with equally impressive leaves, but these are the ones you’re most likely to come across in garden centers.

Rex Begonia FAQs

Check out the following FAQ for more useful tips about the health and requirements of painted leaf begonias:

Are Rex Begonias Prone to Diseases & Pests?

Not really. Rex begonias have a good pest and disease resistance if growing requirements are met. Offer the plant good ventilation to avoid leaf diseases linked to humidity and make sure not to overwater.

The problems you may encounter with rex begonias include mealybugs (sapsucker pests that can be removed using a cotton ball soaked in alcohol), root rot (caused by overwatering), leaf blight (caused by a temperature contrast between day and night), and powdery mildew (fungal problem caused by high humidity in the absence of air circulation).

In case of fungal issues, you will usually need to use a fungicide to get rid of the problem. Of course, you’ll also need to make adjustments and increase ventilation while also maintaining the high humidity levels the plant requires.

Most of these issues can be avoided by strictly observing the plant’s growing requirements.

How Long Do Rex Begonias Live?

Most begonias will only live 2-3 years, even with stellar care. Therefore, you can take the time to propagate your rex begonia, especially if it’s an interesting cultivar that you don’t want to part with.

Are Rex Begonias Toxic?

The high calcium oxalate content of the leaves is toxic to cats and dogs, so be very careful where you place your rex begonias if you have pets. Also keep them away from kids. Ingesting the leaves of rex begonia plants can cause vomiting, drooling, and even kidney failure in severe cases.

Do Rex Begonias Require Pruning?

Painted leaf begonias don’t usually require pruning, except when the plant is turning out to be leggy, which usually happens when the plant is not getting enough light.

Always rotate the plant so it’s evenly reached by light and prevents leggy growths. If you still experience problems, you need to change the location of the plant to a place where it can get bright indirect light.

Pinching back the leggy growths will help the plant grow fuller once you also move it to a location where it can get more light.

Conclusion

Rex begonias are a flamboyant plant with many features to please the eyes. Some cultivars can be very finicky, especially when it comes to humidity, but there are varieties that aren’t as demanding.

Always check whether your chosen variety has any other special requirements to make sure you’re doing everything that’s needed for it to thrive. Rex begonias produce small flowers that are pink or white and usually have few petals.

Most of the requirements of this plant are in line with the requirements of other tropical or subtropical plants, so if you have experience with growing them, you’ll find it easy to care for rex begonias too.

Updated: March 25, 2020

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