Begonia Black Mamba Plant Care Guide

Last Updated on April 18, 2022 by Admin

The Begonia Black Mamba is a rare plant. it features black colored foliage that is very uncommon with most plants. It also produces pink flowers which makes for great contrast in color.

The plant is a cross between the Begonia Dr. Cleo and the Begonia Peggy Frost.

How do you care for the Begonia Black Mamba? It needs plenty of light. Keep it in bright indirect light indoors and partial shade outdoors. This will allow it to maintain its stunning black flowers.

The plant enjoys warm, humid environments and moist soil. But don’t get the soil soggy as the plant is prone to root rot.

Begonia Black Mamba Plant Care

Light Requirements

The Begonia Black Mamba thrives in bright, indirect light indoors and partial shade outdoors.

Note that the amount of light you get in your home is very different from outside. That’s because of the ceilings and wall. Thus, natural light can only come in through the windows or any other access.

This limits the amount of light indoors.

Thus, bright light indoors it nowhere near the bright light outdoors. As such, many growers will tell you to give the Begonia Black Mamba shade.

When they say this, they are referring to outdoors where the plant will grow best in partial shade.

Hopefully, that clears things up since I’ve gotten quite a few questions about this.

As for the Begonia Black Mamba, you want to give it plenty of light indoors. However, avoid very strong light as it cannot tolerate more than a couple or so hours of this on a daily basis.

As such, try to avoid direct sunlight during the middle of the day. It will have no problems with direct sun during early mornings and late afternoons as these are much gentler.

This is why the east and west facing windows are usually the best options for the plant.

You can likewise keep it towards a southern exposure. However, keep it at least 3 feet or more away from the window opening. This allows it to avoid the direct rays of the sun.

Don’t leave the plant in direct sunlight for hours at a time between 10:30 a.m. to 3:30 p.m. as this kind of exposure it too harsh.

It will cause the Begonia Black Mamba’s dark leaves to fade. And they may even get scorched.



As with most begonia varieties, the Begonia Black Mamba is native to tropical and subtropical regions.

Therefore, it likes consistently warm weather.

Its ideal temperature is between 65 to 75 degrees Fahrenheit. And it won’t mind higher temperatures as well. However, try to avoid conditions of 90 degrees Fahrenheit or higher if possible.

Its preference for consistently warm conditions makes it easily fit into indoor living. That’s because humans enjoy moderate to slightly warm environments. And this is why homes have this kind of temperature.

However, the outdoors is a bit trickier.

That’s because a lot depends on the climate changes where you live.

The Begonia Black Mamba loves USDA Hardiness Zones 10 and 11 because these regions have consistently warm and sunny weather even during November through March.

This makes these zones perfect for growing the Begonia Black Mamba outdoors.

But if you live anywhere colder, the plant is often kept indoors as a houseplant.

You can still take it outdoors around mid to late spring once the weather warms up outside. Although, make sure to bring it back indoors once the cold weather starts around mid to late fall.

The plant will struggle when it gets colder than 50 degrees Fahrenheit. So, you don’t want to leave it outdoors especially in winter.



The Begonia Black Mamba likes humidity. And its ideal level is between 60% to 80%.

Although, it will do well in 45% to 50% humidity as well.

That said, try to avoid dry air since the lower the humidity the less the plant is able to flourish.

If humidity in your home happens to stay low, you can likewise increase it around the plant to keep it happy.

Note that you don’t need to up the humidity in your entire home or even for the entire room.

Instead, just the surrounding air around the plant will be sufficient.

Simple ways to increase humidity include moving the plant to the bathroom or the kitchen. You can likewise mist the plant regularly will keep it happy.

My favorite method is to set up a humidity tray or pebble tray. Both work the same way but with different apparatus.

They’re likewise simple to make. It takes up 15 minutes to set up either. And you can use items you already have at home.




How Often to Water Begonia Black Mamba

The Begonia Black Mamba likes soil to kept evenly moist. Be careful not to add too much water or water the plant too often.

I know some beginner gardeners who misunderstand moist to think it is on the wet side. This is very dangerous as the plant is prone to root rot.

And root rot is primarily caused by overwatering.

Therefore, avoid watering too often at all costs. This is the worst thing you can do to the plant.

As such, the best way to water the Begonia Black Mamba is to allow the top 1-2 inches of soil to dry between waterings.

By letting the soil dry slightly before you add more water, you reduce the risk of watering too often.

The other half of watering is how you water.

Here, avoid wetting the leaves. Don’t water the plant overhead wetting all the leaves in the process.

Instead, pour directly on the soil.

Additionally, when watering the Begonia Black Mamba, you want to water thoroughly.

This means drenching the root ball until you see liquid start trickling down from the drainage holes at the bottom of the pot.

Then allow the soil to completely drain after that.

This 2-step method of wearing ensures that the roots get all the water they want. But that the excess moisture quickly drains out after to avoid waterlogging or overwatering.

This leaves you with moist soil and roots that are well-hydrated.


Begonia Black Mamba Potting Soil

The Begonia Black Mamba needs rich, well-draining soil that has good aeration. It also likes soil pH between 6.1 to 7.5.

Good drainage is very important as the plant is prone to root rot.

Therefore, the soils ability to quickly get rid of excess moisture helps prevent problems from happening even on days you happen to add a little bit too much water.

An easy way to create this soil mix at home is to combine:

  • 2 parts peat moss
  • 1 part sand
  • 1 part loam

This will allow the soil to hold some water to keep soil moist. But at the same time, it allows excess moisture to drain quickly to avoid overwatering.

Besides using the right soil, it is also important that the excess liquid has a way to get out of the pot.

Otherwise, the water will just pool at the bottom of the container and keep the soil wet anyways.



The Begonia Black Mamba will appreciate fertilizer. And it will grow faster with the nutrients it gets.

The plant is not picky about the kind of fertilizer as long as it gets the nutrients it needs.

So, there are many different options you can go with here.

The most common home gardeners will use is a balanced fertilizer. Dilute this to 50% each time you apply to avoid overconcentration.

This way you can prevent over fertilizing the plant.

Apply once a month during spring and summer. Stop feeding the plant around early to mid fall. It does not need fertilizer during winter.

The most important thing to remember here is never over fertilize the plant this can eventually cause harm by damaging the roots.



The Begonia Black Mamba will grow to about 12 to 18 inches high and have a spread of 18 to 24 inches from side to side.

It is not a large plant but its leaves can get quite big relative to its size.

The largest leaves I’ve seen on a Begonia Black Mamba were nearly 12 inches in length.

This makes the plant impressive.

Since the leaves make up most of the plant’s size, you don’t want to prune a lot of these.

Only prune those that get a bit unruly.

Outside of that, you’ll only need to remove the old, discolored, diseased and dead leaves.


How to Propagate Begonia Black Mamba

Begonia Black Mamba propagation is usually done via leaf cuttings or rhizome cuttings.

You can do either since they both work.

Although, you kind of end up with different things after you propagate them.

With leaf cuttings, you’re almost starting from scratch since the new plant will have to start developing roots first then the rest of the parts.

On the other hand, with rhizome cuttings, you get part of the rhizome with roots. And this comes with stems and leaves above the soil as well.

Therefore, you start with a semi-grown smaller plant.

This puts you many steps ahead since the rhizome cutting and grow shoots and leaves from there.

Here’s how to propagate Begonia Black Mamba from rhizome cuttings.

  • Begin by taking the plant out of the pot. You can likewise choose a few leaves and trace down the stem to see which area of the soil the stem goes into. With the latter, just dig up that part and you have access to the rhizome.
  • Once you take out the plant from the pot, remove excess dirt and soil clearly see the rhizome.
  • You can now choose the section you want to cut. You don’t need to get a big section. Just choose a small cutting of the rhizome. But make sure it has enough roots to support the leaves above it.
  • Sterilize a knife or blade then cut the rhizome at that section.
  • Once you have the rhizome cutting, plant it into a pot filled with well-draining potting mix.
  • Water the soil and keep it moist. And place the pot in bright, indirect light.

Since the rhizome cutting is semi-grown, you don’t need to wait for it to root.

In a short while it will begin producing new shoots then leaves.


How to Repot or Transplant Begonia Black Mamba

The Begonia Black Mamba likes being slightly root bound. Therefore, there is no hurry to repot the plant.

On average, you only need to repot it every 2 or 3 years.

Although it is a good idea to take the plant out of the pot and replace the spent soil annually to refresh is with new, well-draining soil.

If you do, you don’t have to move the plant to a larger pot.

This way the soil stays porous and has good drainage without getting compacted. You also gets to replenish the nutrients and replace the depleted ones.

If the plant is root bound, then move the plant to a larger container.

The best time to repot is spring.

When choosing a container just go up one pot size. Also, make sure the pot has drainage holes at the bottom so the excess moisture can escape.

Avoid overpotting the plant size excess size increases the risk of overwatering.

Additionally, a much larger pot will tell the plant to keep growing its root system. While this is not bad, it also makes the plant focus more energy and resources of root development not foliage growth.

I’m not sure about you, but with the Begonia Black Mamba I would like the plant to focus as much as possible on its foliage since that’s it best point.


Is It Toxic/Poisonous to Humans, Cats & Dogs

Yes the Begonia Black Mamba is toxic to humans, cat and dogs. But only when ingested.

Therefore, it is important to keep kids and pest away from the plant so they don’t end up playing around it and eating the leaves.


Related: How to Care for Dragon Wing Begonia Plant


Begonia Black Mamba Problems & Troubleshooting


The Begonia Black Mamba is not very prone to pests. But it can experience them just like other houseplants.

The most common pests that bother the plant include spider mites, scale, thrips, mealybugs, snails and slugs.

As such, you want to keep an eye out on the plant and inspect it every now and then.

If you see any, treat them with insecticidal soap spray. I like to use Castille soap but you can use any mild dishwashing liquid as well.



The Begonia Black Mamba can also experience diseases. Many of these are caused by excess moisture.

So, you want to be careful with excessively high humidity, overwatering and wet leaves. All of these increase the risk of one or more of these infections.

When it comes to foliage, watch out for bacterial leaf spot and blight, nematode, botrytis and powdery mildew.

The plant is prone to these leaf disease.

Also, it is susceptible to rot, these include pythium rot and rhizoctonia crown rot.

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