The Begonia Bipinnitifida or Fern leaf Begonia is a special species of Begonia that will be appealing to rare and particular plant lovers. Native to New Guinea it was first discovered growing in the high rocky environment of Mount Horne.
Its name bipinnatifida perfectly describes it’s twice pinnate leaves that look like they belong to a fern rather than a Begonia. Its stems are a deep red color and the leaves are deep green on the top and deep red on the bottom.
This finicky and delicate plant has a long list of needs and wants and will be a handful even for the most experienced of growers. It will do best in an enclosed terrarium or greenhouse for that very reason. If you are ready to take on the challenge and are ready to learn what the Begonia bipinnatifida really needs to thrive keep on reading.
It might not be easy but if you crack the fern leaf Begonia code it will be very rewarding.
Table of Contents
Begonia bipinnatifida asic plant care instructions
Soil
For a Begonia bipinnatifida you will have to provide a soil mix that consists of one part long-fiber sphagnum moss, one part regular soil, and some perlite for aeration.
The sphagnum moss need special preparation, you have to boil it to sterilize it and then cut it into roughly one-inch pieces. Blot the sphagnum moss with paper to dry it out a little bit and combine it with the perlite.
You should also provide a layer of charcoal at the bottom of the soil. The charcoal will have the role of absorbing excess soluble salt and other minerals that can damage the roots.
You can then pour the moss and soil mix into the pot or dedicated terrarium space and plant your Begonia bipinnatifida.
You should check the pH of your soil annually. This is easily done since you can purchase pH testing kits in any garden center. If the pH falls below 5.8 you should add some ground limestone to the soil. Do this carefully and gradually until the pH is restored to the correct level.
Light
Begonia bipinnatifida likes a lot of light. Supposing you are planting it in a terrarium the place that is most brightly lit is usually close to the center of the terrarium.
You can also try to plant it as high as possible so it is close to the source of light. If you have a timer you should set it to 14 to 16 hours of light a day.
These will be the perfect conditions for your Begonia bipinnatifida. If you are a brave heart and want to try to plant it in a pot, put it in an east-facing window in the summer and a south-facing window in the winter.
Be careful not to put it too close to a window though, they dislike sudden changes, and temperatures next to windows can drop and rise suddenly. It can also get too hot for them on a windowsill during the summer.
Watering
When grown in a pot a Begonia bipinnatifida will need moderate watering when the top inch of soil is dry to the touch. During the winter they have a rest period when you should water less and allow the top half of the soil to dry before watering.
Make sure you are not leaving the soil soggy, as Fern leaf Begonias hate having wet feet. I suggest watering it above a sink and letting all of the excess water flow through the drainage holes of the pot.
If you planted your Begonia bipinnatifida in a terrarium you won’t need to worry about watering as much. Terrariums are generally self-sustaining and will take a lot of work out of taking care of such a delicate plant.
When the top of the terrarium medium is dry to the touch you can add some water with a fine mist of rain or distilled water and this should do the trick.
Temperature
The Begonia bipinnatifida will do well in normal room temperatures from 50 to 95°F. If you planted it in a terrarium you should be worried about overheating rather than cold shocking this plant.
Terrariums tend to heat up since they are a closed glass environment. Sunlight from outside and the lightbulbs from inside can potentially heat up the terrarium so much to cook your plants alive.
This is why terrariums are usually placed in colder places in the home away from windows and heat sources. You could also set the lights to turn on during the night when it is generally colder.
If nothing else helps, consider getting a fan that will disperse the heat and keep the terrarium cool.
Humidity
As mentioned before, one of the main reasons for growing a Begonia bipinnatifida in a terrarium or greenhouse is it’s extreme humidity requirements. It likes a minimum of 70% humidity and will thrive with even higher, 80, or 90% humidity.
Pebble trays will not do the trick and if you don’t want to live in such high humidity yourself I am going to guess trying to achieve that with a humidifier indoors is not realistic.
If you do not have a full-blown terrarium with all of the bells and whistles, you can try to make do with a regular glass container that can be closed. This is going to require a bit more attention and upkeep than a full-size terrarium. You will probably need to mist and ventilate the container weekly.
Fertilizer
Feeding your Begonia bipinnatifida if it is in a terrarium is more than likely not necessary. As mentioned before terrariums are pretty self-sustaining.
If you are growing it in a pot in a greenhouse or indoors I recommend fertilizing every two weeks with a regular liquid fertilizer diluted to one-third of its strength. Be very mindful as this plant is delicate, and it can quickly get fertilizer burn if you pour the fertilizer onto dry roots.
I always fertilize my plants after watering them, so that the fertilizer evenly disperses through the soil.
Propagation
Although it is a high maintenance plant, Begonia bipinnatifida propagation is a piece of cake. If you are growing it in a terrarium, propagate it by stem or leaf cutting and just stick the cutting in clean sphagnum moss.
I usually wrap the stem in sphagnum if it is a small cutting, being careful that the entirety of the bottom stem is in contact with the moss. You can use a nylon thread to secure the moss around the cutting.
Keep this contraption evenly moist but not wet and put it in a very humid warm environment with plenty of light. A corner in your terrarium is the safest place for it.
If you are growing your Fern leaf Begonia in a pot, your best bet it taking stem cuttings.
Like for many other plants, this is best done in spring or early summer. I outline the process below:
- Choose a stem that is at least two to three inches long and has a couple of leaves. As always make sure it is healthy and pest-free.
- Cut just below a leaf and trim the bottom leaves to reveal a node.
- Dip the cut in a rooting hormone powder that you can get in any garden center.
- Prepare your new pot. The growing medium for such a cutting should be one part sphagnum moss and one part perlite or sand. This is also the time to pre-moisten your soil.
- Place your cuttings in the pot making sure the nodes are in contact with the growing medium. Enclose your new cutting with its pot in a plastic bag or propagation box and keep it in bright indirect light.
- In about three to four weeks you should notice developed roots and new growth, you can now remove the plastic bag and treat it as an adult plant. Do not repot it yet, wait for the next season for better chances of success.
Growth
These Begonias have a bushy or shrubby growth pattern and generally remain small in size. You can expect it to reach a maximum of 10 to 12 inches in height.
Potting
Potting this plant is a tricky business. I have probably mentioned this before but Begonia bipinnatifida does not like being moved and handled.
Exercise maximum caution and handle it delicately while repotting. If you give it the best conditions, you can expect to have to report it every spring, but check beforehand if it is needed at all.
You can do this by looking underneath the pot and checking if any roots are peeking through the drainage holes. When your Begonia bipinnatifida is ready for its new pot, prepare the pot beforehand.
Put a layer of coarse gravel and charcoal at the bottom of the pot and a layer of growing medium. Then carefully transfer the plant without shaking or picking at the roots, there is no need to remove the old growing medium.
When your plant is in its new pot, instead of pressing or overly manipulating the plant, sprinkle some of the new growth medium around the roots and tap the pot to settle the mixture. Do not apply pressure with your fingers or try to compress the soil.
If you notice there is not enough soil down the road you can always add some more.
Common problems with Begonia bipinnatifida
Unsurprisingly this Begonia is also very prone to powdery mildew and other fungal and bacterial diseases. This is because of its high humidity and temperature requirements.
To achieve such requirements we grow such plants in enclosed containers and consequently sacrifice some ventilation and airflow that are much needed for the prevention of such issues.
Other problems you might run into while caring for your Begonia bipinnatifida are root rot and bacterial leaf spot, so let’s get into more detail about all of those and see what you can do to prevent and treat your plant.
Powdery mildew
Powdery mildew manifests itself with round, white, fluffy spots on your Begonia bipinnatifida’s leaves. Like for most fungal and pest issues on houseplants you should try to prevent the problem before it occurs.
When you are setting up your plant make sure it is not too close to other plants and that there is enough air circulation to move the air around. If the issue occurs in a terrarium, make it a habit to open it regularly for half an hour to an hour or provide a small fan.
When the mildew is already there and you noticed early enough you can make a homemade remedy that consists of 1 tablespoon of baking soda, ½ teaspoon of liquid soap, and a gallon of water. Dunk a cotton round in this mixture and wipe the mildew off of the affected leaves. Repeat this once a week until the mildew doesn’t come back.
Pythium root rot
This is another fungal issue that is a threat to your Begonia bipinnatifida. Roots and stems can turn brown and rot when the plant is overwatered or the roots don’t have enough oxygen.
This creates a perfect environment for pythium root rot to develop. Initially, you might notice your plant turning yellow and wilting. If you have just watered your plant and it doesn’t recuperate, check the roots of the plant.
Healthy roots are strong and light of color from the stem to the bottom. If you find any brown or black roots these should be removed as soon as possible and the rest of the plant washed to remove any remaining spores.
You should re-pot your plant into new sterile soil that is more aerated than the one in which the plant got sick, to fix the issue. You could also consider a fungicidal treatment.
Bacterial leaf spot
Bacterial leaf spot will cause round, black or brown, water-soaked spots with a yellow margin. It can cause the rotting of leaves and stems.
If the disease is already present there is not much you can do other than remove the affected parts of the plant. If the whole plant is affected the best course of action is throwing it away before the bacteria spread to the other plants.
Prevention includes good air circulation, watering in the morning, and easing off on the fertilizer for a while.
How to keep your Begonia Bipinnatifida problem-free
- Grow your Begonia in a terrarium or greenhouse
- Provide ample ventilation and airflow
- Water in the morning
- Fertilize with diluted fertilizer
- Handle only when absolutely necessary
- Keep away from drafts and sudden temperature fluctuations
Frequently asked questions about Begonia bipinnatifida
How do I know if I overwatered my Begonia Bipinnatifida?
If you are keeping your Begonia bipinnatifida in a terrarium a good sign of overwatering is a build-up of condensation on the glass after watering. This means you added too much water. Use a paper towel to wipe the excess water from the terrarium and leave it open for a couple of hours to let it dry.
How to prevent mold and fungus on a Begonia bipinnatifida in a terrarium?
Many don’t know that Neem oil can be used in terrariums too. Neem oil is an excellent, organic, and biodegradable fungicide, bactericide, and feeding deterrent for pests. When used in a terrarium dilute it to half or a third of its strength and wipe the leaves and stems of your plants with it.
Where is the best place in a terrarium for a Begonia Bipinnatifida?
Since these plants love a lot of light the best place for a Begonia bipinnatifida in a terrarium is somewhere in the middle of it where it can get plenty of light. If you can plant it in an elevated spot it will be even better, as this will further lower the chances of your Begonia Bipinnatifida experiencing wet feet.
Does this all seem like a lot? Because it is. A begonia bipinnatifida will be a very exotic and interesting addition to your plant collection, but it will make your work for the glory.
If you want to make your Begonia bipinnatifida thrive provide it a terrarium and this will immensely alleviate the burden or the numerous peculiarities this plant requires. If you are up for the challenge, watch out for the mold and root rot, and provide a high humidity environment for your Begonia bipinnatifida.
If you already have one and you have pictures or more tips and tricks, please share them with us if our Facebook group, we love hearing from you!