How To Grow Begonia maculata (Polka Dot Begonia): Complete Care Guide

If you’re looking for an interesting and beautiful addition to your houseplant collection, look no further than Begonia maculata. It’s relatively easy to grow and care for and is sure to add a splash of interest to any home. In this guide, we will discuss how to grow and care for Begonia maculata, including how to identify and solve common problems.

Begonia maculata: All About the Polka Dot Begonia

Begonia maculata, also known as the Polka Dot Begonia, is pretty easy to care for and makes a beautiful houseplant. Native to Brazil, this plant is part of the begonia family, which includes almost 2,000 species of begonia (most of which are grown for their flowers).

Begonia maculata, however, is known for its beautiful, colorful foliage. Its olive green leaves have red undersides and are covered in silver polka dots (hence the name “Polka Dot Begonia”).

How Big Does a Polka Dot Begonia Get?

These plants start out small, but mature Polka Dot Begonias can reach four or even five feet tall.

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How Do You Take Care of a Begonia maculata?

In a nutshell, this plant needs bright indirect light, to be kept moist but not wet, and should be planted in a well-draining potting mix.

Let’s take a deeper dive into the care requirements:

Light Requirements for Polka Dot Begonia

Begonias prefer bright indirect light. They can tolerate medium- to low-light conditions but won’t thrive.

However, too much sun will cause the leaf spots to fade (and you definitely don’t want that to happen since the polka dots are the main feature!) So be cautious about placing it near a window where it gets a lot of direct light.

Maintaining the right light balance will ensure that your plant remains showy and beautiful.

If you notice it becoming leggy or the colors fading, that’s a sign that it needs more light. So, move it to a brighter spot.

Temperature Requirements

This plant is native to Brazil, so it’s used to warm weather. It prefers temperatures between 70-85 degrees Fahrenheit and does not do well in drafty or cold areas.

If the temperature drops below 60 degrees, the plant will go into shock and may die. So, if you take it outside for the summer, bring it in when the nighttime temperature drops below 60 degrees.

How Much Water Does Begonia maculata Need?

It prefers to be moist but not wet. I recommend letting the top inch of soil dry out between waterings. Overwatering can lead to root rot, so it’s important to err on the side of caution. 

Yellow leaves and moldy soil are signs of overwatering.

On the other hand, If the leaves start to droop, that’s a sign that it needs more water.

You should also be aware that they don’t like getting their leaves wet. I like to use the bottom watering method, but you can water from the top if you’re careful to avoid the leaves. A long-spout watering pitcher makes it easier to avoid the leaves if you prefer top watering.

The Best Pots and Soil

The best pot for your begonia is heavy enough to balance the weight of the upright stems. You don’t want it to tip over and break!

I’m a fan of terra cotta or glazed ceramic, but anything heavy enough to support the plant is a good choice. Begonias don’t like sitting in water, so the pot must have good drainage.

It prefers a well-draining potting mix that’s rich in organic matter. Never use garden soil for indoor plants. Instead, use a commercial potting soil mix containing peat moss and either perlite or vermiculite.

Fertilizing Requirements

I like to fertilize my begonias every other week during the growing season with a half-strength solution of a balanced houseplant fertilizer. However, be sure not to over-fertilize, which can cause leaf burn.

They don’t need to be fertilized during the dormant season (e.g., the winter months).

Humidity Preferences

Humidity is important; after all, these plants are native to the tropics.

The ideal humidity level is between 50% and 70%. If the humidity level is too low, the leaves will dry out, and the plant will become stressed.

However, if the humidity level is too high, the leaves will become mushy, and the plant may develop fungal diseases. For example, Begonia maculata is particularly susceptible to powdery mildew, which thrives in damp conditions.

To maintain the ideal humidity level, use a humidifier, or place the pots on a tray of pebbles filled with water.

Pruning

One of the most important things you can do for your begonia is to prune it regularly. Pruning helps to promote new growth and keeps the plant from getting too leggy.

To prune, simply cut the stem back to the desired length with sharp scissors or pruning shears. Late autumn is the best time to prune.

To encourage new growth, cut above a node.

Repotting

Your plant will need to be repotted every one to two years. Repotting helps refresh the potting mix and allows the plant to continue growing.

When repotting, choose a pot that is only one size larger than the current pot. However, begonias do like being a bit root-bound, so you may just want to refresh the potting soil without going up a pot size.

To repot, simply remove the plant from its current pot and replant it in the new pot with fresh soil. Water well to help settle the roots into their new home.

Propagation Tips

Begonia maculata can be propagated relatively easily.

I’ve found that the best way to propagate them is by taking stem cuttings from healthy plants.

To do this, simply cut a 4-6 inch section of stem from the mother plant, making sure to include at least one node (preferably more) and at least one leaf. Make the cut using sterilized pruning shears, about 1/4 inch above a leaf. You can cut a single stem or take multiple stem cuttings.

Stem cuttings can be rooted in water or potting mix.

How To Propagate in Water

This is my preferred method of propagation. Simply place the stem cutting in a jar of water. Make sure the leaves stay out of the water. Place the jar somewhere that gets bright, indirect light. I typically root plants in my kitchen window because it gets morning light.

Change the water every few days to keep it fresh. You may also need to top off the water from time to time as it evaporates from the jar.

It can take several weeks for roots to develop, so be patient!

Once the roots are two or three inches long, you can transplant the cutting into potting mix.

How To Propagate in Potting Mix

To propagate begonias in potting mix, fill a small pot with a well-draining potting mix.

Water the soil until it is moist but not soggy and then gently press the stem cutting into the soil so that at least one node is buried. The roots will develop from the node.

You can dip the cutting in rooting hormone before placing it in the potting soil to speed up the process. Keep it warm and make sure it gets consistent moisture. Within a few weeks, new roots will develop.

Flowers

This tropical plant is best known for its beautiful leaves. However, under the right conditions, it will bloom, producing clusters of white flowers with yellow centers on a single step. 

If your plant hasn’t bloomed, be patient, make sure it gets plenty of bright light, and fertilize it regularly.

Diseases and Pests

These plants are relatively easy to care for. Still, there are a few common issues that can occur, mainly diseases but also some pests. Below are some tips on how to prevent these problems from happening.

Diseases

The begonia is susceptible to a few different diseases, which we’ll cover below. The best way to prevent disease is to make sure your plants get enough light and airflow and avoid wet conditions.

Powdery Mildew

Powdery mildew looks like white powder on the leaves. It can be caused by too much shade, not enough ventilation, or overly wet conditions.

If you notice powdery mildew on your begonia, try moving it to a brighter location and increasing the airflow around the plant. You’ll also want to remove any affected plant material so that the mildew doesn’t spread.

You can also treat powdery mildew with a fungicide.

To prevent powdery mildew, make sure your begonia is getting enough light and avoid getting the leaves wet when you water. Lastly, make sure that the top of the soil is dry before you water again.

Botrytis

Botrytis is a gray mold that affects begonias (and other plants) when grown in cool, damp conditions. The best way to prevent botrytis is to ensure your begonia is getting enough light and ventilation (are you noticing a theme here?).

You should also avoid overcrowding your plants and water them from below so that the leaves don’t stay wet. Lastly, be sure to remove any plant debris from the top of the soil.

If you notice tan or brown spots on the foliage or stems, then your plant probably has botrytis blight. In that case, cut off any affected plant material immediately and throw it away. Then treat the plant with a fungicide.

Bacterial Leaf Spot

Bacterial leaf spot can cause serious problems for your plant. The symptoms include brown or black spots on the leaves, and the leaves may also curl up or drop off. The best way to prevent this disease is to water your begonia from below. This will keep the leaves dry, which will help to prevent the bacteria from infecting the plant.

You should remove any affected leaves as soon as you see signs of bacterial leaf spot. You can also treat the plant with a copper-based fungicide. Finally, make sure to disinfect any tools or equipment that you use on your begonia to avoid spreading the disease.

If the plant is severely affected, you may be better off discarding it.

Stem Rot

Stem rot is caused by a fungus, and it can quickly kill your plant if it’s not treated promptly. You’ll notice that the stem turns brown and mushy, and the leaves will start to droop. If you see these symptoms, it’s essential to act fast. Cut off any affected parts of the plant, and dispose of them in a plastic bag. Then, treat the plant with a fungicide.

To prevent stem rot, ensure your begonia is planted in well-drained soil and avoid overwatering.

Pythium Root Rot

Pythium root rot is a serious disease that can infect begonias, causing the plants to wilt and die. The disease is caused by a water mold called Pythium, which thrives in wet, humid conditions.

Symptoms of Pythium root rot include yellowing leaves, stunted growth, and root rot. The disease is most likely to occur in poorly drained soils, so it’s important to make sure your plants have good drainage and aren’t sitting in soggy soil.

If you notice any signs of the disease, remove affected leaves and roots immediately. This is another instance where you may be better off discarding the plant because this disease spreads quickly.

Pests

The begonia is also susceptible to a few different pests, the most common being mealybugs and whiteflies for indoor plants. In addition, aphids could be a problem if you take it outside in the summer.

Because begonia foliage is sensitive, I wouldn’t suggest using a pesticide spray unless you test it first on an inconspicuous leaf. Bonide Systemic Insect Control is a good general-purpose pesticide, but use caution if you have kids or pets around.

Common Problems

Yellow Leaves

One of the most common problems people have with their Begonia maculata is yellow leaves. This can be caused by several factors, including too much or too little water, incorrect light levels, or even under-fertilization.

Overwatering is the most likely cause, so check that first. Begonias like moist soil, but they don’t like to be soggy. Allow the top inch of soil to dry out a bit between waterings.

If you’ve ruled out overwatering, check the light levels. If the plant is getting too much sun, move it to a shadier spot. If it’s not getting enough sun, move it to a sunnier location.

And finally, it may just need to be fertilized.

Leggy Stems

Begonia maculata can become “leggy” over time, meaning that the stems become long and thin. The plant can become difficult to manage and may even lose its foliage when this happens. Leggy stems are typically caused by insufficient light.

If your plant has become too tall and leggy:

1. Move it to an area where it gets plenty of bright, indirect light. If you don’t have a place that gets lots of indirect sunlight, you can use a grow light or even regular indoor lighting.
2. Prune the leggy stems back to about six inches. This will encourage the plant to produce new, shorter stems.
3. Fertilize the begonia after pruning to encourage new growth.

Crispy Leaf Tips

Brown and crispy leaf tips are a sign that your plant needs moisture.

Here’s what you can do to prevent dry leaf tips

1. Make sure the plant is getting enough water. The leaves will turn brown and crisp if the plant is thirsty.
2. Check the humidity level around the plant. Begonias like humid conditions, so the leaves will suffer if the air is too dry. If the humidity level is too low, try placing your plant on a pebble tray.
3. Avoid placing the Begonia maculata in direct sunlight. The leaves will scorch if they get too much sun.

Toxicity

Begonias are toxic for dogs and cats. The most toxic part of the plant is the root, so it’s not too likely to cause problems. But if you have pets who like to nibble on plants, it’s best to keep them away from this houseplant.

How To Purchase a Healthy Begonia maculata

Now that you know everything there is to know about Begonia maculata, you’re ready to go out and get your own! Here are a few tips for purchasing a healthy plant.

• Start by inspecting the leaves for signs of pests or disease. Avoid any plants that have yellowing leaves or crispy leaf tips.
• Check the stems to make sure they’re not leggy. You want a plant that is compact and full of foliage.
• Make sure the soil is moist but not soggy.

Wrapping Up: Care Summary

Begonia maculata is a beautiful plant that can make a striking addition to your indoor plant collection.

It’s susceptible to a few diseases, but you can keep your begonia healthy and thriving with some simple care tips.

• Be sure to water it regularly, but don’t let it stay wet.
• Place it in an area with plenty of indirect light.
• Use a well-draining potting mix and repot it annually.
• Fertilize it every two weeks during the growing season with half-strength fertilizer.

With a bit of love, your begonia will be a beautiful addition to your home for years to come!

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