Ever since the discovery of the first begonias, myriad gardeners and plant lovers have continued to collect distinct and interesting species of the family Begoniaceae. One such species is Begonia amphioxus, extremely widespread in tropical and subtropical climates. It has been increasingly cultivated indoors ever since the introduction of central heating and that remains the case today.

Care highlights: This winter-flowering shrub-like species is rare in cultivation and truth to be told, it is a bit of a demanding grower. It requires warm conditions to thrive, bright to moderate light, shaded from direct sun, and slightly higher humidity. Plant it in an open, fibrous growing medium, preferably in a humid greenhouse or a terrarium. It is not hardy or frost-tolerant. The best method for Begonia amphioxus propagation is via stem cuttings or seeds. Slow-release fertilizers are recommended for an additional supply of nutrients. Watch for gray mold, powdery mildew if conditions are too damp.

Here’s what you will learn in my article:

  1. Description of Begonia amphioxus
  2. Preferred places for cultivation
  3. What’s the best temperature for this plant?
  4. Does it require high humidity?
  5. What type of lighting is ideal for Begonia amphioxus?
  6. Container and growing medium
  7. Is repotting complicated?
  8. How to water Begonia amphioxus properly?
  9. Does it require regular fertilizing?
  10. Multiple propagation methods
  11. Common pests and how to get rid of them
  12. Keeping the plant in good shape
  13. Frequently asked questions

Continue reading to find out all bits of information you need to grow healthy and happy Begonia amphioxus.

Description of Begonia amphioxus

Begonia amphioxus is a unique-looking perennial, shrub-like species of the genus Begonia.

Martin Sands introduced the plant into cultivation in 1984 and gave it its very appropriate name amphioxus which means “sharp at both ends” referring to the leaves of the plant. In the wild, it only occurs on two small, limestone outcrops in Malaysia and it can grow up to 75 cm tall.

Foliage

This particular variety of Begonia is grown for its distinctive foliage. Stems are green and glabrous, that is, hairless. Stipules are usually ovate-lanceolate, which means much longer than wide, and fall off quickly. Typically, leaves are peltate, ans sharp at both ends, which explains how the plant got its name.

Besides, the foliage has wine-red spots and thin-lined rims of the same color. Marvelous, isn’t it? The contrast between red and green is jaw-dropping. That’s also why the plant got the name “Butterfly plant”, by analogy with the markings on the leaves and the manner in which the leaves sway in the wind.

The leaf blade itself is angular-ovate and petioles pale green and hairless, up to 6 cm long.

Begonia Amphioxus foliage

Inflorescence

Inflorescence is axillary, unisexual. Male inflorescences are few-flowered, cymose and there are 4 tepals greenish-white in color. On the other hand, bracteoles in the female inflorescence are absent, there are 3 to 5 tepals greenish cream in color.

In order to grow any begonia successfully, it is of utmost importance to recognize what type of condition it needs. The plant’s appearance and its natural habitat can provide relevant insights into that matter.

Begonia amphioxus inflorescence

Before I get down to explaining care essentials, allow me to introduce you to other members of the family:

What follows is a detailed guide on how to care for Begonia amphioxus!

Preferred Places for Cultivation

Outdoors

The easiest way to grow most begonias, including Begonia amphioxus, is in a greenhouse or in a shade house. Since this is a shrub-like variety, you can also plant it in the ground and dig it up before the winter. However, most begonia species are not suitable for outdoor cultivation in frost-prone areas.

Indoors

Contained-atmosphere and artificial-light gardening can work for humidity-loving species in the home. For instance, you can grow Begonia amphioxus in glass and plastic containers, including goldfish bowls or large cookie jars, with the top sealed with plastic wrap or a pane of glass so that moisture remains inside.

The containers are then placed under horticultural fluorescent lights. Alternatively, you can position them near a window, but choose the site carefully, bearing in mind that in its natural habitat, Begonia amphioxus grows in light shade. Also, remember that cultivating plants in contained atmospheres will slightly alter the way you should care for the plant.

For example, the plant will need less frequent watering and the care of enclosed containers is minimal as far as repotting and fertilizing are concerned. Using distilled or rainwater is advisable in this case and you can touch the soil surface to see if it is dry. Water only when it becomes dry.

If you are growing Begonia amphioxus in a terrarium, which is a preferred way because of high humidity, fertilizing is rarely necessary. Being a small variety, it can even be planted in a hanging basket or a standard-sized pot.

There is a wide array of options to choose from depending on the resources that are available to you. While a humid greenhouse or a terrarium is preferable, you can still grow Begonia amphioxus in a standard pot. Make sure that you take the place where the plant is growing into account before you decide upon the routine that you will be following.

Keep your Begonia amphioxus indoors

What’s the Best Temperature for this Plant?

Begonia amphioxus is not cold-hardy and certainly not frost-tolerant. The optimum temperature for cultivating one is from 13 to 29 degrees C, while nighttime temperatures should be lower than the daytime temperatures. If you are growing the plant in a greenhouse, you can use wet pads and fans to decrease temperature levels.

Does it Require High Humidity?

Begonia amphioxus requires a relatively high level of humidity, between 40 and 60 percent. One of the reasons this plant variety prefers sealed environments such as terrariums is that moisture is kept inside and humidity levels are higher.

If your plant lacks humidity, leaves will turn crispy, with brown margins, even leaf drop. Grouping plants together and growing them on humidity trays also help to increase humidity.

On the other hand, if the environment is too humid, your plant is likely to be infected by fungus and other bacterial diseases, including leaf rot. In that case, you can install fans to reduce humidity.

What Type of Lighting is Ideal for Begonia amphioxus?

The last of the three interrelated variables mentioned above is light. This plant species requires well-lit conditions to thrive. They should not receive bright direct sunlight, but rather, it should be indirect or filtered, for instance by netting or trees.

Shading Begonia amphioxus is necessary in summer and spring, especially if you live in northern regions, but in fall and winter, the plant will need little or even no shading whatsoever.

For optimum growth, place your plant beside an east-oriented window in the summer and a south-facing position in the winter. The reason for that is that east-facing windows are a lot cooler than south-facing or north-facing ones. 

It is important to note that recognizing when a plant is being grown under the wrong light levels. If it is receiving too much light, leaves will be pale, bleached, and have brown margins. In some cases, the plant can exhibit red pigments on stems and leaves.

On the other hand, if it is receiving less light than needed, the foliage will be unnaturally pale, growth is poor and there will be a lack of flowers. Observe the appearance of the plant and experiment with different spots until you find the ideal one.

Artificial light

You can grow begonias under artificial light in case they don’t receive enough exposure to the sun. Bear in mind that light levels are the most intense right under the center of the light. Lights should be at a reasonable distance of around 40 cm from the Begonia amphioxus.

In case artificial light is your only source of light, you can keep it on for 12-14 hours per day. However, you can reduce it temporarily to 12 hours a day for two months. That’s during the winter season to promote flower production. Additionally, you can use timers to regulate the exposure that your plants receive.

Finally, for many plant growers, light stands provide a space-saving means of cultivating plants indoors. Position your plants close to each other on trays with artificial lights suspended above them. Drape a sheet of plastic around them to increase humidity.

Related: Grow Light Guide

Container and Growing Medium

For shrub-like species like Begonia amphioxus, it is best to use a slightly deeper pot.

There are lots of options for containers available – porous clay pots allow the excess water to evaporate from the growing medium, while plastic pots hold moisture and the plant needs less watering as a consequence. You can try both options and see which one works best for you.

As for the growing media, it should be slightly acidic (pH 5.8–6.8), light, well-aerated and free draining.

There are two options- to buy a ready-made mix, loam or peat-based, or make your own.To do that, you can use sphagnum moss which adds acidity to the mix, then sand, grit, bark, or perlite to promote good drainage and increase air circulation.

If you are growing the plant in a greenhouse, it is advisable to make or buy the mix that contains 7 parts sphagnum peat, 2 part grit (small, sharp stones), 1 part bark, a little slow-release fertilizer, and a little ground limestone. This mix is used by the staff of the United Kingdom’s National Begonia Collection at Glasgow Botanic Gardens.

However, if you are growing your Begonia amphioxus in a terrarium, the soil requirements and the general care of the plant differs. You need a porous growing medium which contains chopped, long-fiber sphagnum moss and a modest amount of perlite.

Begonia amphioxus soil requirements

Prepare the soil by following 5 simple steps

  1. Put the moss in boiling water to sterilize it. Allow it to cool so you can divide it with scissors into approximately 2.5-cm-long pieces.
  2. Remove any excess water before mixing it with the perlite. Use newspapers or paper towels.
  3. Line the base with a 6-mm layer of small charcoal pieces.
  4. Add 2.5-7.5 cm of the chopped sphagnum-perlite mix on top of the charcoal.
  5. Since the medium is still moist, no additional watering is needed after planting.

Is Repotting Complicated?

It is time to repot when the roots have filled the container that Begonia amphioxus is growing in. Use a container that is only slightly larger than the previous one, but not too large. Replace the old soil with fresh, adhering to what has already been said.

Related: Does Potting Soil Go Bad?

How to Water Begonia Amphioxus Properly?

Climate, growing medium, the type of container, and species influence how much water your green friend needs. As a general rule, begonias grown in pots should be watered when the top half-inch of their growing medium has become dry to the touch.

Water the plant sufficiently and allow the excess water to drain from the bottom of the pot so as not to damage the root system. Keep in mind that water should be warm, not cold or hot, which can cause a shock for the plant.

If you are in doubt, slightly pull the plant out of the pot to see if the soil is dry or moist. Water Begonia amphioxus infrequently and sparingly in the winter.

Does it Require Regular Fertilizing?

When plants are actively growing, they will benefit from the addition of quality fertilizer.

For Begonia amphioxus and other members of the family, water-soluble fertilizers that contain nitrogen, phosphorous, and potassium in a ratio of 20-10-20 are ideal. Read the instructions that come with the fertilizer and if you are an inexperienced gardener, you can reduce the strength of the fertilizer so as not to damage the roots by overfertilizing.

You shouldn’t apply fertilizers in the following situations:

  • If the plant has just been repotted, but rather wait for at least a month
  • In case the plant is sick
  • When your Begonia amphioxus is dormant

Multiple Propagation Methods

Stem cutting

  1. Use a sharp, sterile knife to prepare the cutting.
  2. Remove the tip of a healthy, actively growing stem or branch 5–15 cm of the non-flowering stem with roughly two to five nodes.
  3. Trim off the lower leaves.
  4. Place the cut end, which should be just below a node, in the rooting mix – liquid or solid. Before doing this, be sure that the basal node has a dormant growth bud, not a scar left from an inflorescence, which will be reluctant to produce roots.
  5. Roots should form at the cut end after a few weeks, then the cutting is ready to be potted.

Pro-Tip: Stem cutting is more effective than leaf cuttings as far as shrub-like begonias such as Begonia amphioxus are concerned.

Seed propagation

Many begonias are obtained via seeds. So, seed propagation works pretty well with begonias, including Begonia amphioxus.

  • Find an adequate, draft-free spot so that your seeds don’t blow away.
  • Prepare a seed tray or a pot.
  • Choose a suitable sterile seed mix, such as one comprised of equal parts of sand and peat. Sterilize the mix by placing it in an oven at 16–21°C in a shallow baking pan covered with aluminum foil for about an hour.
  • Level and gently firm the surface of the mix.
  • Use warm water to thoroughly wet it. You can either use a watering can or soak the pot in a tray of water.
  • After the medium has drained thoroughly, sow the seeds by sprinkling them evenly across the surface of the moist medium.
  • Begonia seeds need light to germinate, so they should not be covered with the medium.
  • Place the container with the seeds in a humid, well-lit environment.
  • A pane of glass or plastic film placed on top of the container will help increase humidity.

The seeds of many Begonia species will start to germinate within two to three weeks, but some take up to a year.

Related: 35+ Propagation Hacks that Will Blow You Away

What should you do once the first leaf has developed?

Once the Begonia amphioxus seedlings have developed their first or second true leaf, transplant them into new trays or pots so that they are about 1.3 cm apart.

Gently lift the seedlings out of the original seed mix and position them in a small, ready-made hole in the new medium. The humidity should be gradually decreased to approximate that which the adult plant will receive.

Once the seedlings have reached about 3.8 cm in height, they should be transplanted a second time, so that each plant occupies its own 8-cm pot. Repotting Begonia amphioxus is repeated each time the young plant reaches the limits of its new pot.

Pro-Tip: With all forms of propagation, always remember to add labels to trays and pots to provide a record of what is being propagated and a means of learning from each experience. Recording on the label the date the seed was sown is especially beneficial.

Common Pests and How to Get Rid of Them

Typically, pests are more likely to find their way to your plant if you are growing it in a large glasshouse with a huge number of plants. However, you can easily get rid of any Begonia amphioxus problem, provided that you deal with it in a timely and efficient manner.

Mealybugs

Wipe affected parts of the plant using a cotton swab soaked in rubbing alcohol. The other way is to dip the plant in a solution of soapy water and alcohol. Continue this treatment as long as necessary. Horticultural oils and insecticidal sprays can also be used to treat large infestations.

Mites

Remove any infected plant parts and then spray with an acaricide specifically recommended for the control of the problem mite. General insecticides rarely prove effective at controlling mites. Quarantine new plants to prevent infestations.

Nematodes

There are two types: root and leaf nematodes, both of which resemble worms. They thrive in warm and humid environments and move from plant to plant.  Clear indicators that nematodes infected your plant are stunted growth, the overproduction of red leaf pigments, the foliage is discolored, wilting, and they can even attract bacteria and fungi.

Remove dead and dying parts, avoid overhead watering as a means to safeguard against them, routinely sterilizing potting soils, and washing plant pots. In case they appear on the roots, it is best to destroy the affected plant.  If you decide to try and save the plant, remove all contaminated soil and pot, infected parts, sterilize new material and quarantine the plant to confirm that it has indeed recovered.

Scale insects

Luckily, those are easy to identify by the covering of wax that protects eggs and honeydew. They should be treated the same way as mealybugs in Begonia amphioxus.

Snails and slugs

These creatures usually occur in open gardens. A sprinkling of soot or diatomaceous earth around the base of the susceptible plants will deter these pests. Some other options are setting beer traps, removing dead and dying plant material.

Weevils

They feed on begonias at night, producing a characteristic marking on the edge of the leaves. You can remove them by hand, while playing a pest detective, inspecting them at night, silently, with a flashlight. Working insecticides into the potting medium whenever plants are repotted is also recommended, as well as watering appropriate liquid insecticides into the potting mix. This can be done periodically from July to October when weevils are the most active.

Whiteflies

Those are powdery, moth-like insects that make leaves yellow-spotted and cover them with sticky honeydew, causing leaf drop. Wasp Encarsia Formosa can help with these, as well as insecticides, although some brands don’t prove to be effective.

Diseases

Bacterial leaf spot can occur in the summertime when humidity and temperature are extremely high. Isolate the infected plant, remove and destroy infected parts, and if the condition is serious, spray the plant with a bacterial leaf spot treatment. Avoid splashing water on the leaves when watering.

Powdery mildews produce white patches on the leaves, stems, and buds. They prefer high humidity, wet leaves, cool temperatures, and healthy plants. Avoid overhead watering and provide good air circulation and ventilation. Fungicides can help if the condition becomes serious.

Before you encounter any problems with your plants, it is useful to know how you can prevent them.

7 Steps to Prevent Pests and Diseases

  1. Purchase healthy, pest- and disease-free plants and plant material
  2. Maintain hygienic conditions for growing  and routinely tidy the greenhouse
  3. Avoid overhead watering
  4. Avoid splashing water on leaves
  5. Use sterilized potting soils
  6. Regularly remove dead and dying leaves, as well as flowers
  7. Regularly inspect plants for pests, especially the root system and the leaves

Keeping the Plant in Good Shape

This part of plant maintenance includes pinching and pruning.

Pinching – removal of stem tips promotes side branching. Pinch back when the plant is young so that in their adulthood they will be more compact and attractively looking with enhanced flowering.

Pruning – removal of whole stems or large parts of stems. Prune when the plant becomes too large for its growing area or when it lacks balance in appearance.

Pro-Tip: It is advisable that you label your plants, too, if you have a huge collection. You can use any plastic label and write the name, family, source, and date of acquisition.

Frequently Asked Questions

Conclusion

Begonia amphioxus is definitely not a beginner plant due to the care it requires, depending on whether you are cultivating it outdoors (in a glasshouse) or indoors (in open versus sealed environments). This is a deciding factor in determining the routine you need to adopt, but regardless of where you are growing it, you should know how the plant should look throughout the year and be able to recognize when it is growing poorly.

To do that, note down the prescribed care requirements and observe how the plant is reacting. Cultivating it will be a slightly harder yet enjoyable experience because the plant will give you food for thought.

Are you already a proud owner of Begonia amphioxus? What’s your experience with this lovely plant? Share it with me in the comments section below!

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