Alocasia Infernalis (Black Magic care TIPS)

top view of an alocasia infernalis plant with dark almost black colored elephant ear leaves in a small pot

The Alocasia Infernalis is a VERY unique, goth-like houseplant.

Infernalis literally means “from hell” referring to this plant’s dark green-red, almost black leaves that have an amazing fiery red sheen when the light hits at certain angles. Move it a little again, and the fiery red color disappears. It’s amazing to watch (BUT so hard to capture on camera)!

A newcomer to Jewel Alocasias, this Borneo-native grows up to 22 inches (55 cm) tall. They come from wet lowland forests, growing in leaf litter and clay loams.

Care-wise, this compact Alocasia loves medium levels of indirect light (North-facing windows), orchid bark-based soil, and light monthly fertilizing. Water only when topsoil is dry, and check frequently for pests.

Let’s dive into the details!

Alocasia Infernalis vs Azlanii

A quick note on differences between a couple of look-alikes.

side by side comparison between the alocasia alzanii (left) and the alocasia infernalis (right)
Alocasia Azlanii (left) versus Alocasia Infernalis (right)

The Alocasia Azlanii is another beautiful, low-growing Alocasia with dark leaves. The easiest way to tell its an Azlanii, NOT a Infernalis, is to look for purple veins and a light green leaf border!

Also, the Azlanii is usually A LOT more expensive, around US$100 for a starter pot. The Infernalis is usually US$15-20 on Etsy! You can always tell the difference with the price tag 😛

Alocasia Infernalis vs Cuprea

side by side comparison - left hand side, an alocasia cuprea and on the right, an alocasia infernalis
Alocais Cuprea (left), versus Alocasia Infernalis (right)

Both Cuprea and Infernalis have dark colored leaves that, in the sunlight, look coppery or reddish! But the easiest way to tell the difference between the two is the color of the leaves away from the light.

Cupreas tend to have a lighter, more brownish color than Infernalis. Infernalis leaves also tend to look more matte and less shiny or glossy than Cupreas…. after all, the Cuprea is known as the “Mirror Plant” for a reason!

How to care for your Alocasia Infernalis

Light

Having darker-colored leaves, the Alocasia Infernalis doesn’t need BRIGHT light. It prefers lower light levels.

Ours is propped against a North-facing windowsill where it gets plenty of indirect light. (North or East-facing windows are best for Infernalis.)

If you have a sunny West-facing window, you can use a shadecloth to dapple the light. Otherwise, artificial lighting is also effective!

Water

Alocasias (like many houseplants!) are sensitive to over-watering, so it’s important to be mindful of the amount and frequency of watering.

topview of the alocasia infernalis

When and How to Water

  1. Water only when you feel, using your fingers, that the top 2 inches of soil is dry. Or, use a moisture meter.
  2. Water slowly and deeply, allowing water to escape from the drainage holes.
  3. Empty the saucer.

Importantly, check the soil moisture every few days, so you know when your plant is starting to get dry again.

If the topsoil is still a little moist – resist the temptation to water and check back in a day or two. Only when the topsoil is dry should you water your plant.

Water Quality

Water quality matters to your Alocasia Infernalis, which has fragile roots. Ideally, use purified water, or rainwater. Otherwise, use tapwater that has been left out overnight, allowing harsh chlorine and fluoride salts to dissipate.

In all cases, use room-temperature water. Too-cold water is like taking a too-cold bath: unpleasant! 😛

Humidity

If the air in your home is dry, you may need to take extra measures to increase the humidity around your plant. Ideally, keep your Infernalis in humidity >60%.

One way to do this is to use a humidifier – or check out other ways to raise humidity.

Temperature

The best temperature for the Alocasia Infernalis is between 65 and 85 degrees (18-29 degrees C)!

Also, keep this Alocasia away from areas where the temperature can suddenly change, or there are cold drafts. For example, near a drafty door or under a heating or cooling vent is NOT a good idea.

Drops below 60 degrees (16 degrees C) can induce dormancy.

Seasonal Dormancy

If you live in a country with seasons, the Alocasia Infernalis becomes dormant at the end of autumn and throughout the cold winter months. This means it is conserving its energy and isn’t actively growing.

Leaves may shed and die back; this is normal and DOESN’T hurt the plant.

Dormancy is triggered by low temperatures and low light levels. Your Alocasia senses that growing conditions are not optimal, so decides to conserve its energy.

During this time, ensure your plant is in as warm a spot as you can find, reduce watering and stop fertilizing. It will bounce back during spring! 🙂

Growth Rate

At maturity, this low-grower only reaches 20-22 inches (51-55cm) tall. Its a perfectly eye-catching plant for a small space.

In our experience it has an average growth rate.

Flowering

You’ll know you’re an amazing plant parent if you see your Alocasia flowering. This is a rare occurrence, and happens only when the plant is mature and thriving. It’s basically a sign that its so happy that it wants to reproduce!

Truth be told though, the Alocasia Infernalis infloresences are not everyone’s cup of tea. The spathe and spadix combination of most aroids fall short of what one might think of when it comes to showy or ornamental flowers. 😛

You can cut these off if you wish – but it’s up to you! Either way, pat yourself on the back knowing you’ve done a great job caring for your Alocasia.

Soil or Growing Medium

We prefer a HEAVILY barky mix, so that water can drain freely through your Alocasia’ soil.

We use a combination of:

  • 3 parts orchid bark
  • 1 part horticultural charcoal
  • 2 parts indoor potting mix (we like the moisture control version below)
Miracle-Gro Moisture Control Potting Mix, 1 cu. ft. Miracle-Gro Moisture Control Potting Mix, 1 cu. ft.
$19.97
Pros:
  • Protects against over- and under-watering
We earn a commission if you make a purchase, at no additional cost to you.
12/17/2022 12:00 am GMT

Fertilizer

We find that the Alocasia Infernalis is not a heavy-feeder, but likes to feed constantly. Fertilize once every 2 weeks using a gentle (urea-free, remember those fragile roots!) liquid fertilizer at 1/3 strength.

Fertilize only in active growing months (spring and summer). Don’t fertilizer in fall and winter – this is important!

Choose a fertilizer that is high in nitrogen (but still nutritionally complete), as nitrogen promotes healthy foliage growth.

Our favorite is Dyna-Gro Grow, which we use for most of our houseplants.

If you prefer a truly organic option – we’ve also had success working worm castings into the potting mix. 🙂

Repotting

Given that your Alocasia Infernalis is a Jewel Alocasia (small and low-growing), it doesn’t need to be repotted often.

Do note that repotting stresses your plant out. It will need time to recover and establish itself again. Your plant also likes to the slightly root-bound, so you don’t need to be in a rush to repot!

Only when you see roots peeking out of the drainage hole should you start thinking about repotting. Repot in spring, and water your plant the day before so that it can easily dislodge from its pot.

Toxicity

According to ASPCA, all Alocasias, including your Alocasia Infernalis, are toxic to animals and humans when ingested.

This is no thanks to calcium oxalate crystals in your plant’s stems and leaves. These insoluble crystals pierce tissues, causing skin irritation, severe nausea, vomiting as well as gastrointestinal pains.

If you are looking for a pet or kid-friendly plant, check out Peperomias, Calatheas and Hoyas.

Propagation

Alocasias are a tuberous plant that have underground rhizomes that can be propagated. If you’ve never seen a rhizome before, they are modified stems that grow underground and look like ginger.

They store food and grow offshoots, which are new baby plants.

To propagate your Alocasia Infernalis, we use rhizome division, which is literally slicing off a part of the tuber to make a new baby plant.

You can also harvest bulbs in the soil that grow into baby plants – but obviously this takes longer to grow, about a month.

A few reminders before we get into propagation steps:

  • The best time to propagate is early spring, early in the growing season.
  • As with repotting, propagating stresses your plant out. So, only attempt propagation when you have a healthy and mature plant.
  • Don’t propagate if you have a new plant or recently relocated it.

Propagation through Rhizome Division

  1. The day before propagation, water your plant and sterilize a knife blade with 70% isopropyl solution.
  2. Place your plant on its side and unpot your Alocasia Infernalis. Use your fingers to gently tease out the soil to reveal the rhizomes. Try not to damage the roots.
  3. Using the sterilized blade, cut off a portion of the tuber that has a few stems and some established roots. (In some cases, you can be able to SIMPLY separate the roots on an established plant without cutting.)
  4. Repot the tuber in evenly moist potting mix. Choose a pot that is suitable for the size of the tuber, and one that has drainage holes.
  5. Place the mother plant back in its pot.
  6. Keep both plants in a warm, humid location with plenty of indirect light. If you have a humidifier, place it next to the plants and set at 80%.
  7. It will take about 2-4 weeks for roots to establish in the baby plant, and for your mother plant to recover. Your plants may show signs of stress in the meantime.
  8. New growth indicates your plants have recovered!

Propagating through Bulb Harvesting (or Corms Harvesting)

  1. When repotting your plant, opportunistically look for any bulbs hidden in the soil. They may be tangled in the roots.
  2. Select bulbs that are hard and round, and that are easily picked off. These characteristics signal that your bulb is ready to grow.
  3. Place the bulbs in a separate pot. Keep the soil evenly moist.
  4. In a month or so expect to see new growth!

Pruning

Being a small plant, there’s not much pruning that needs to be done.

But if you spot a damaged or diseased leaf, cut this off with sterilized shears. This helps your plant focus its energy on new, healthy growth.

Common Pests and Issues

Alocasia Infernalis is a middle of the road plant when it comes to pests and diseases. It’s not particularly susceptible to pests, but it’s not SUPER tolerant to infestations either.

Do inspect your plant for pests before bringing it home.

alocasia infernalis leaves

Moisture-related Issues

We find that the most common issues for Alocasias are moisture-related. Too much moisture often leads to fungal root rot and may also invite leaf spot disease.

The best way to prevent this is to ensure you’re watering your plant correctly and using a super chunky soil mix (see our recommendation above!).

Bacterial Leaf Spot

Too much moisture can lead to bacterial leaf spot. According to the University of West Virginia, early signs of infection are water-soaked legions on leaves.

This bacterial infection spreads most rapidly in wet and humid environments, which, unfortunately, are the very conditions that your plant likes…

To reduce the risk of infection, water your plant near the soil line, and avoid wetting the leaves. Refrain from misting your plant.

To treat, quarantine the plant to avoid contamination, snip off infected leaves and dispose of these securely. Then, apply a copper-based fungicide to prevent its spread.

It’s a good idea to sterilize all your gardening tools with 70% isopropyl solution to prevent the infection from spreading to your healthy plants.

Pests!

Alocasia Infernalis may suffer infestations from the usual suspects – aphids, spider mites, fungus gnats and mealybugs. The most common of these is spidermites and mealybugs.

A preventative measure is regularly using dilute neem oil to ward off these pests. Here’s how.

We also always keep a bottle of Bonide Insecticidal Soap spray around for infestations – luckily, it is effective against all these pests.

Frequently Asked Questions

Is the Alocasia Infernalis rare?

Well, it’s not an Alocasia we typically see at local (non-specialist) gardening centers. They are not as popular as Alocasia Frydeks, as an example.

But you can find them easily on Etsy, and they aren’t too expensive either, averaging ~US$15-20 for a starter pot with a few leaves.

Where does the Alocasia Infernalis come from?

It comes from wet lowland forests of Borneo, Southeast Asia.

What is Alocasia Infernalis Red?

Sometimes, Alocasia Infernalis is labelled “Alocasia Infernalis Red”, referring to the reddish color its leaves have in the light. It is the same species.

Sometimes growers add descriptors to the scientific names of plants, but they are the same species. Other examples include, “Alocasia Infernalis Black Magic”.

Other Alocasias we Love

Wrapping Up

The Alocasia Infernalis is a stunning dark-leafed Jewel that has a reddish sheen in the light. To keep it looking its best,

  • Providing it medium indirect light. North-facing windows are ideal.
  • Giving it as much humidity as possible (>60%, ideally higher at 80%)
  • Locate it in a warm spot away from winds and drafts.
  • Regularly check for pests.
  • Allow it to be slightly root-bound.
  • Choosing an airy and free-draining potting mix with plenty of bark.
  • Checking the soil moisture frequently, and water only when topsoil is dry.
  • Water using purified room-temperature water.
  • Choose a gentle liquid fertilizer, applying once every 2 weeks at 1/3 strength during growing season.
  • Do not mist!

Deborah is a plant enthusiast and founder of Gardening Collective.