Growing and Caring for Begonia Maculata (Your Final Guide!)
Begonia maculata, also known as polka dot begonia, spotted begonia, or trout begonia, is an attractive plant that can elevate any garden. It is well-known for its angel-wing-shaped leaves, white spots, and easy-care nature. But how easy is ‘easy’?
Begonia maculata grows in well-drained soil, indirect bright light, 65–85°F temperature range, and at least 45% humidity. Watering should only be done every 4 days to avoid the development of diseases. Meanwhile, it is best to apply liquid slow controlled-release fertilizer every 2 to 4 weeks. Pruning polka dot begonia can be done twice a year.
Polka dot begonia, like any other plant, may have garden problems. What exactly are these issues? What are the best ways to deal with them? Scroll down to learn more about this aspect!
How to Care for Begonia Maculata
Watering, lighting, soil, fertilizer, temperature, relative humidity, and pruning are all factors to consider when caring for polka dot begonia.
For you to have a quick look, I have summarized the recommended conditions for optimum growth and development of begonia maculata in the table below.
| Factors | Recommended Conditions |
|---|---|
| Watering | Water every 4 days (keep the soil moist, do not overwater) |
| Lighting | Indirect, but bright (west-facing window) |
| Soil | Houseplant potting mix (perlite can be used as soil amendment) |
| Fertilizer | Apply every 2-4 weeks (use liquid fertilizer) |
| Temperature | 65°F to 85°F |
| Relative Humidity | Above 45% |
| Pruning | Twice a year |
More of this will be discussed in the next sections, so read forward!
Watering
For begonia maculata, a controlled watering schedule of every four days is recommended. Using this schedule, the soil can be kept moist but not soggy, reducing the chances of overwatering.
If there is one thing that I have learned from houseplant gardening for the past years, it is avoiding over and underwatering.
Thus, it is important to know the best watering frequency for your specific plant. In begonia maculata’s case, it is every 4 days.
Another thing to remember when watering polka dot begonias is to never leave your plant in a water-filled pot saucer.
This is a common error for most gardeners because they think that it is a way for their plants to be low maintenance. However, this principle does not apply to all plants.
Overwatering can cause root rot. But how healthy plant roots should be?
Lighting
Polka dot begonias do not thrive under intense direct sunlight. Therefore, it must be located in an east or west-facing window, where there is indirect, bright light. It can grow well with only 3 hours of this specific light exposure.
A critical factor in lighting is the amount of morning sun your begonia plant receives. This can be provided by east-facing windows.
On the other hand, west-facing windows give afternoon light, which is also good for polka dot begonias.
Soil
Begonia maculata needs moist, well-drained soil, thus, a regular houseplant potting mix could be used. Soil amendments such as perlite can also be added if the soil is too compact.
Having well-drained soil is key to helping control water in your begonia maculata plant. You must have a loose soil structure because overwatered begonia plants are prone to root rotting, which can lead to plant death.
However, if you already have compact soil, one way to increase the drainage of your soil is to add soil amendments. Examples of these materials are perlite, coarse vermiculite, small clay pebbles, and pumice.
Explore more on perlite in our article on perlite facts.
Compare other growing mediums in our article on perlite substitutes.
This potting mix on Amazon is one of the bests since it has perlite in the mix which provides adequate aeration and drainage. This is also suitable for growing in containers.
Fertilizer
The best nutrient form to use on begonia plants is liquid fertilizer, applied every 2 to 4 weeks. Ideally, a liquid fertilizer for polka dot begonia should contain at least 10% nitrogen, 10% phosphorus, and 10% potassium.
Liquid fertilizers like the one below on Amazon is a controlled-release fertilizer that is ideal for indoor plants.
Do not fall for the mistake of using a huge amount of granular fertilizers. These fertilizers, when used excessively will result in nutrient and salt buildup in your soil.
Now, how will this affect your begonia maculata plants?
The salts in your soil will clog the roots of your begonias, preventing them from properly absorbing water and oxygen. When this occurs, the leaves turn yellow and eventually wilt.
Transplanting
It is recommended to transplant or repot polka dot begonia once a year. This is actually a simple yet effective way to prevent diseases from growing and reproducing in begonia maculata plants.
How does it help? When you transplant, you are also providing your plants with new and cleaner soil to grow compared to its soil for a year.
Another advantage of repotting polka dot begonias is improved soil structure.
Consider soil that has been watered for a year. It tends to become compact at some point. Thus, repotting begonias is necessary to provide them with fresh soil in which the roots can be better aerated.
Discover more on repotting in our article on dying herbs after repotting.
The best pot for begonia maculata is plastic pots. This is because they are lightweight, easy to maintain and clean, and are also cheap. The best pot size for begonia maculata is at least 12 inches. Below is a suggested pot from Amazon.
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Pruning
Because polka dot begonias are leggy, pruning the top portion will encourage lateral growth of leaves. Pruning the begonia plant is best done in autumn or when the plant has grown too tall.
In pruning begonia maculata, you can use pruning shears or a high-quality regular pair of scissors.
3 Ways to Propagate Begonia Maculata (With Instructions!)
Begonia maculata can be propagated in homes and gardens using leaf cuttings, stem cuttings, and division.
If you already noticed, polka dot begonia can be easily propagated using asexual reproduction. This means, these plants are multiplied from plant parts, and not seeds. Below are simple guides in propagating begonia maculata.
1. Stem Cuttings
In order to multiple begonia plants using stem cuttings follow the following steps:
- Choose a healthy begonia plant.
- In a 45 degree angle, cut stems that are 2 to 4 inches long.
- Remove any leaf in the stem. (This is necessary because the leaves will prevent root emergence by competing for plant resources.)
- Clean the stems with distilled water.
- Prepare your sterile growing medium (e.g. perlite, coco coir, or vermiculite)
- Place the stem cuttings on the growing medium tray in an upright position.
- Moist with distilled water when the growing medium dries.
- Keep the growing tray in a humid and cool place.
- Wait for roots to grow.
2. Leaf Cuttings
Here is a simple guide in propagating begonias through leaf cutting:
- Choose a healthy leaf.
- Cut the leaf up to its stalk.
- Using a sterile blade, create small slashes on the main vein (this is the thick stalk at the middle of the leaf).
- Pin the whole leaf on the growing medium (e.g. compost, coco coir, potting mix)
- Moist this setup.
- Keep the growing tray in a humid and cool place.
- From the slashes, roots will develop, and leaves will grow.
3. Division
Begonia maculata can also be propagated using division. Here are the simple steps.
- Choose a healthy stem with more than 2 stalks and leaves.
- Separate each stalk from the other.
- Place each separated stalk in separate growing containers (e.g. pot, growing tray) with potting mix.
- Water them.
- Wait for new growth to emerge.
9 Common Problems in Begonia Maculata
Common problems in begonia maculata include yellowing of leaves, drying of flowers, bacterial leaf spot and blight, botrytis blight, powdery mildew, pythium rot, viruses, foliar nematodes, and pests.
1. Yellow Leaves
Yellow leaves in polka dot begonia could be attributed to overwatering, too compact soil structure, and water-logging due to absence of drainage.
You can do the following to make sure that your begonia maculata will not turn yellow:
- Water only every 4 days
- Use well-aerated potting mix (you can use perlite to improve aeration)
2. Drying of Leaves and Flowers
When flowers of begonia maculata are browning and drying, it could be a result of intense direct sunlight, underwatering, and salt stress.
Consider the following factors if you want to prevent the drying of leaves and flowers in polka dot begonia:
- Avoid exposing your begonia maculata plant to direct sunlight.
- Do not allow your soil to dry for more than four days.
- Do not over-fertilize.
3. Bacterial Leaf Spot and Blight
Bacterial leaf spot and blight in begonia maculata display watery spots with a yellow halo surrounding them.
Here are the best ways to prevent the spread of bacterial leaf spots and blight in polka dot begonia.
- Buy disease-free plants. (Tip: Do not buy plants with the symptoms)
- Remove diseased plants in your garden quickly.
- When watering, avoid wetting the leaves.
- Infected plants should not be propagated (either by stem cutting, leaf cutting, or division).
4. Botrytis Blight
Among botrytis rot’s symptoms in polka dot begonia include the rotting of cut parts of stem cuttings, tan leaf spots, and development of grayish dust on the leaf surface.
Botrytis blight will not develop and reproduce if the following measures are done.
- Keep the relative humidity low by spacing the plants from each other.
- Provide good air circulation using vents.
- Remove all dying flowers or leaves. (They may harbor diseases in them!)
5. Powdery Mildew
Powdery mildew is commonly observed on the stems, leaves, and flowers of begonia maculata. It is characterized by the development of white powder. When the white powder has affected a large portion of the leaves, a fungicide can be applied.
If you are looking for a fungicide that can control this disease, you can try the one below on Amazon which I have been using ever since.
6. Pythium Rot
Pythium rot could be present when the majority of begonia maculata seedlings die with black and shiny spots on the leaf surface and stems. Prevent pythium rot by following the optimum watering schedule of every 4 days.
So how is pythium rot connected to the watering schedule?
Pythium rot develops in areas with so much water. Thus, if you are overwatering your begonia maculata, you are also providing a favorable condition for pythium rot to occur!
Learn here how to clean a pot after root rot!
7. Viruses
Viruses, such as the mosaic virus, infect the begonia maculata plant if it develops a mosaic pattern on the leaves, wrinkled leaves, light yellow ring spots, general yellowing, and stunted growth.
Here are some preventive measures for viruses that can infest your polka dot begonia.
- Do not purchase polka dot begonia with the abovementioned symptoms.
- Always sterilize the growing medium to prevent virus spread.
- Control insect pests because they spread the virus.
- If plants have already developed symptoms, discard all infected plants by burning them. Do not mix them in your compost because the virus will spread further.
8. Foliar Nematode
Foliar nematodes infest the polka dot begonia plant when stunted growth and excessive red coloration and brown spots on the leaves are observed.
To avoid foliar nematodes, you must avoid water splashing onto the leaves and overhead irrigation. This is because the water droplets may be a breeding ground for the nematode.
Most importantly, when you observe some leaves already showing symptoms, discard them quickly!
9. Insect Infestation
Insect pests of begonia maculata include scales and mealybugs. Some indicators of infestation to watch out for are white webbing, black droppings, and silver streaks. Neem oil spray can be used to control them.
If you notice these indications on the surface of your polka dot begonia leaves, you can spray them every week with insecticidal soap. This product is available on Amazon, and the one listed below comes highly recommended.
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Neem oil is another useful product that you can use as an alternative. This fantastic product, which I’ve been using ever since, is now available on Amazon.
You can also eliminate the insects by hand with a clean cloth or cotton ball dipped in 70% ethyl alcohol.
FAQs
Where should you cut diseased leaves of begonia maculata?
It is advised to cut infected begonia maculata leaves from the base to allow the plant to redirect its sugar and water resources to the development of new foliage. By doing so, sufficient space is also provided for new shoots and leaves to grow.
Why are my polka dot begonia leaves falling?
The falling of leaves in polka dot begonia can be attributed to excess watering, lack of sunlight, wrong timing of repotting, dehydration, and worm and pest infestation.
How tall can your begonia maculata get?
Begonia maculata plants can grow to be 18 to 24 inches tall. Even though they can reach this height, it is recommended to still prune long stems. Cutting leggy stems stimulates the growth of more stems and leaves.
Does the watering of begonia maculata change from summer to winter?
In the winter, begonia maculata requires less water. As a result, the plant only needs watering once a week. Plants require less water in the winter because they grow slower.
Summary of Growing and Caring for Begonia Maculata
When caring for begonia maculata, one must consider watering, lighting, soil, fertilizer, temperature, relative humidity, and pruning. To avoid polka dot begonia disorders, these factors must be kept in the best possible condition.
Yellowing leaves, drying flowers, bacterial leaf spot and blight, botrytis blight, powdery mildew, pythium rot, viruses, foliar nematodes, and insect pests are all common problems in begonia maculata.
Sources
- “Begonias” by Institute of Food and Agricultural Sciences in University of Florida
- “Begonia Diseases” by Moorman, G.W. in Pennsylvania State University
- “Growing Begonias Indoors” by Shaughnessy, D. and Pertuit, A. in Clemson University
