Begonia amphioxus is a rare, exotic plant discovered in 1984 in Borneo. Its botanical name comes from the words “anthe,” meaning “both” and “axes.” It means pointy, suggesting unusual spear-like leaves tapered at both ends.
Its other names, Pink Spotted Begonia and Polka Dot Begonia, indicate its characteristic dotted leaves.
Begonia amphioxus likes high humidity levels, which makes it an ideal plant for a terrarium or greenhouse. But it can be grown in the open air like other houseplants.
If you want to find out what conditions this little beauty requires, the article will give you all the answers you need!
What Is Begonia Amphioxus?
Begonia amphioxus is a small terrestrial, shrubby herb that grows 18 inches high and 16 inches wide. It has lance-shaped light green leaves with slightly wavy edges, decorated with crimson or maroon dots. The leaves are about 1 to 1.5 inches wide and 2 inches long.
Besides these miraculous leaves, this gorgeous plant has another trump card! It blooms up to three times a year with bright purple or white flowers. The plant is monoecious, which means it has both male and female flowers on the same plant. The delicate small flowers are unusual too – they have sepals instead of petals!
Begonia Amphioxus Care
The essential information about begonia amphioxus care includes:
- A humidity level of 80 to 95 percent
- Bright, diffused light
- Fertilizing twice a month from spring to fall, once a month in winter months
- Watering three times a week in its growing season, less in winter
- Well-drained, nutritious soil
- Repotting every spring
If you want to know more about the listed aspects of growing this charming little plant, let us take a closer look at each of them.
– Humidity Requirements
Begonia amphioxus requires a high level of humidity in the air, 68-80 percent during the day to 90 or 100 percent during the night. It is much higher than 30 percent of the average level in our homes.
The most logical and, at the same time, the most expensive solution is to grow this plant in a terrarium that is a closed system in which you can easily control or change the growing conditions. But it does not mean that you cannot grow this plant without a terrarium!
Here are some of the easy and successful ways that can help you to create an environment with increased humidity levels.
Misting the leaves is functional but risky, as begonias are sensitive to water retention on the leaves and prone to fungal diseases. When you mist the plant, you could use a bottle with a fine spray that turns the water into a haze.
You could mist the plant several times a week, always in the morning, so that the droplets have time to evaporate during the day and do not stay on the leaves for too long.
It is a recommended help in growing most tropical plants. When it comes to begonias, it can also be helpful, but the high percentage of moisture is tempting to maintain constant, and it could be harmful to other plants.
c) Pebble tray
The Pebble tray is one of the simple and effective ways to provide the necessary microclimatic conditions for your Begonia amphioxus. You could place the tray with water and expanded clay under your plant. Water evaporation from the tray will significantly change the moisture level in the immediate environment of the plant.
d) Plastic cover
Begonia amphioxus is not a large plant and is usually grown in smaller pots 5 to 8 inches in diameter. Therefore, the most practical solution is to combine the pebble tray with a plastic cover that allows the moisture from the tray to remain in the plant environment.
In better-equipped garden centers, you can find plastic covers for growing plants that require closed and strictly controlled conditions. DIY covers made from larger plastic bottles will also serve a purpose!
– Water Requirements
The general rule says that you should water your Begonia amphioxus at least three times a week, from spring to fall and once a week during the winter. Regardless, that always depends on all other conditions in which the plant grows. These are temperature, exposure to light, soil permeability, the size of the plant, or the pot in which it grows.
Therefore, adjust the watering regime to each plant. Allow the soil to dry slightly between the two cycles. Begonia amphioxus likes moisture but does not like sitting in a constantly soaked substrate. Water retained around the root system quickly leads to root rot, which is difficult to cure.
a) How to Water Begonia Amphioxus
During watering your Polka Dot Begonia, be careful not to wet its leaves. In high humidity conditions, water droplets remaining on its leaves evaporate slowly, creating very favorable conditions for fungal disease development.
Use a watering can that has a narrow spout and pour water along the edge of the pot directly onto the substrate surface, avoiding the leaves.
Alternatively, you can place the pot with the begonia in another container filled with water and let the substrate absorb as much moisture as it needs. After ten minutes, you can take out the pot, let all the excess water drain out, and put the plant back in its place.
b) Water Quality
Begonia amphioxus does not tolerate tap water because it is hard and contains chlorine and other substances that this plant dislikes. You can water it with lukewarm, soft stagnant water, rainwater, aquarium water, or distilled water instead.
– Soil Requirement
Pink spotted Begonia thrives best in well-drained and nutritious, slightly acidic to neutral soil, with a pH reaction between 6.1 and 7.5. A quality peat mix for houseplants will provide everything this plant needs.
Yet, if you want to improve the structure of the substrate, you can add some limestone chips, oyster shells, or eggshells to the soil. It will help the color of the spots be more pronounced and maintain soil acidity.
– Temperature Requirements
Begonia amphioxus comes from the warm tropical regions of the eternal summer, and it is sensitive to low temperatures, high-temperature oscillations, drafts, and cold air. The optimum at which it feels best ranges between 50-85 degrees Fahrenheit all year round.
That is why a closed system like a terrarium makes it possible to avoid undesirable temperature changes. The begonia sheds all its leaves if you expose it to temperatures below 50 F, even for a short time.
– Light Requirements
In its homeland, begonias grow in the bright shade of high tropical vegetation that protects them from direct sunlight. As a houseplant, they need similar conditions. In other words, you could place it in a very bright spot where it will have a lot of diffused lighting.
Positions next to the north or east window, where it can get some direct mild morning sun, are good choices.
Exposure to the sun in the hottest part of the day will quickly cause burns on the leaves. Therefore, avoid the not shaded south and west windows or place the plant, at least, a few feet away from such windows. Lack of light, on the other hand, causes metabolic disorders.
Without proper lighting, begonia amphioxus grows poorly, stagnant, and eventually withers.
– Artificial light
Artificial lighting is an acceptable alternative if you keep the plant in a place where there is not enough natural light. But make sure that the light source is at least 8 to 12 inches away from the plant to prevent overheating or getting burns.
This plant quickly consumes nutrients from the substrate, so it is necessary to fertilize it regularly. You can use water-soluble fertilizers for houseplants that you could add once or twice a month while watering the plant.
However, be careful to dilute the fertilizer to a quarter of the recommended dose as high concentrations of chemical elements can damage or burn its roots.
Fertilization is vital in the period when the plant is blooming. During that time, the plant needs additional energy and thus additional nutrition. In the winter months, reduce fertilization by half. The natural shortening of the day and lower temperatures slow down the plant’s metabolism, so its needs for additional nutrition are reduced.
Instead of liquid fertilizer, you can also use slow-release balanced granular fertilizer with an NPK ratio of 10:10:10, which you can add to the substrate during transplanting. One teaspoon of fertilizer per 4-inch pot will be enough to provide the plant with the necessary nutrition until the next growing season.
You could transplant your plant every spring or when you notice that part of the root system emerges through the drainage holes.
You can choose a slightly bigger pot and try to ensure that the composition of the substrate is very similar to the previous one. If, after repotting, your begonia stagnates and does not give new leaves for a while, be patient!
Begonia amphioxus does not like changes and takes some time to recover from stress and get used to the new conditions.
Moreover, you can choose from a few simple and effective methods listed below:
1. Leaf Cuttings
- Take a healthy adult leaf with a stalk.
- Insert the leaf into a container previously filled with a mixture of substrate and perlite or vermiculite in a ratio of 1:1.
- Water it and cover it with a plastic bag to maintain humidity.
- Place the container in a warm and shaded place and spray the substrate surface occasionally.
- In the next three or four weeks, the root will begin to form.
2. Stem Cuttings
- Cut the stem from a mother plant two or three inches long.
- Remove all the leaves at the bottom of the stem leaving only two or three leaves at the top.
- Prick the stem halfway into moist soil or sphagnum moss.
- Cover with a plastic bag and place in a warm and well-lit spot.
- The rooting process takes about a month, after which new leaves will appear.
3. Stem Cuttings in Water
Instead of in the substrate, you can put stem cuttings in a glass with clean water. It is a simple method with one great advantage: it allows you to monitor the development of the roots! While the process is going on, add water as needed to maintain the same level.
When the new roots reach half an inch, it is time to plant the new begonia amphioxus in a pot with soil.
High humidity conditions are suitable for powdery mildew and the fungal disease called anthracnose. On the other hand, such an environment does not suit most pests on houseplants, so begonia amphioxus is rarely exposed to their attack.
Thrips are more likely to occur if the plant grows in the open air, outside terrariums, or other protected environments.
The symptoms of the disease are twisted leaves and inconspicuous yellow and brown spots on the leaves. It spreads quickly, so immediately remove all affected leaves. In the next few days, carefully water the plant and avoid wetting its leaves.
If the disease has already advanced, you could remove the most attacked leaves and treat the rest with some of the standard fungicides for houseplants following the instructions indicated.
2. Powdery Mildew
It is a common issue when growing any begonias. Powdery mildew, just like begonias, loves heat and moisture! Fortunately, this disease is rarely fatal to the plant, and you will recognize it by the characteristic white spots on the leaves.
To get rid of this plague, you can try to treat the leaves with a solution of baking soda and water.
Dissolve one teaspoon of baking soda and half a teaspoon of non-detergent soap in one gallon of water, and spray the diseased leaves. The procedure usually needs to be repeated several times, and if the result fails, a fungicide is your next solution.
Thrips are tiny insects that feed on the plant sap and reproduce very quickly. They have wings and can spread to other plants fast. If you notice thrips on the plant, you could try to rinse them under water spray.
However, even after the treatment, some of them survive and continue to weaken the plant. In that case, use natural insecticides such as neem oil solutions. Treat the plant thoroughly, taking care not to leave any part untreated.
With its out-of-this-world appearance, the stunning begonia cannot go unnoticed despite its modest dimensions.
Growing it might require a little experience and patience, but that is no reason not to try to host this real little gem among begonias in your home.
- Provide the high humidity or keep the plant under the plastic cover on the terrarium.
- Avoid the temperature below 55 F, temperature fluctuation, and draft.
- Water it often but carefully since Begonia likes wet but not soggy soil.
- Place your plant in a spot with a lot of diffused light out of direct sunlight or provide it artificial light.
- It is a hungry plant, so feed it regularly.
The Begonia amphioxus is an exotic plant that adds more color to any home. By following our recommendations in this article, we’re confident that your plant will grow healthy and beautiful! Share this article with anyone planning to own a Polka Dot Begonia.
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