How to Grow & Care for Alocasia Macrorrhiza (Giant Taro)

Last Updated on January 15, 2023 by Admin

The Alocasia macrorrhiza is more popularly known as the Giant Taro. But people call it by several names as well including Elephant Ears (for the size of its leaves) and Giant Alocasia.

This Alocasia species a large plant that can grow to 12 to 15 feet high and covering about 6 to 8 feet wide. Its stunning, large leaves are no doubt its most attractive feature.

If you’ve been to Hawaii, you’re probably familiar with the plant as its roots are cooked to create poi, which is a native delicacy in the islands.

That said, the Alocasia macrorrhiza is actually from Southeast Asia and Australia, namely New Guinea, the Philippines and Queensland.

Table of Contents

Alocasia Macrorrhiza Plant Care

Alocasia Macrorrhiza Light

The alocasia macrorrhiza grows best in partial sun or partial shade. Its leaves are prone to scorching under full sun. So, you want to give it some kind of shade or indirect light for the best results.

Similarly, locations that are too dark will cause its huge, beautiful leaves to turn yellow. It will also slow down its growth and increase the risk of root rot. The reasons for the latter is that water takes much longer to dry without sunlight.

The warmth from the sun helps some of the moisture evaporate keep the plant from sitting in water for too long.

In low light conditions, a good way to tell whether there’s enough light is to get a magazine or newspaper. If you can read it, the light is enough. It not, the light is insufficient.

It is also worth noting the direction of the plant’s growth is affected by where the light comes from. As such, overhead light is best as it allows for balanced, upright growth.

Pro Tip: The plant’s large leaves tend to collect dust. So, to improve light absorption, it is a good idea to clean he leaves with a damp cloth every 4 to 6 weeks. Don’t used leaf shine since the plant is sensitive to chemicals.

Alocasia Macrorrhiza Temperature & Humidity

The alocasia macrorrhiza is native to warm temperature regions. As such, for this fast growing plant to sustain is growth, keep the temperature between 65 to 80 degrees. While this will give you the best results, it can tolerate temperatures between 50 and 90 degrees.

This makes it hardy for USDA zones 9 to 12.

Just as importantly, the plant cannot tolerate freezing temperatures. As such, leaving it outside below zone 9 through the winter will kill it.

That said, outdoor time during the summer is great for the plant as it allows it to soak lots of sun. It can take urban pollution so you can do this safely even if you live in the city.

But, when doing so, you need to make sure of three things.

Take it indoors or a warmer location once the weather drops to below 55 degrees.
Keep it sheltered from strong winds which can damages its large leaves.
Avoid direct sunlight which will burn its leaves and increase the risk of dehydration.

The other climate factor to consider is humidity. Here, the plant also enjoys high humidity. But it will tolerate medium to slightly lower humidity.

Still, this can be a problem for some homes especially during the winter when indoor humidity can drop to the 30% to 40% level. If this happens, you’ll notice that the plant’s leaf tips will turn brown and begin to curl.

This is a sign it isn’t getting enough moisture. Thus, you can mist leaves or give its leaves a hosing. If you wet the leaves make sure you put the plant somewhere it can quickly dry. Otherwise, it will increase the risk of fungal disease.

Another option is to use a humidifier to regular indoor air moisture.

Alocasia Macrorrhiza Watering

The alocasia macrorrhiza likes moist soil. But, don’t allow it to stay wet or soggy. While the plant can tolerate some standing water, it isn’t a good idea to keep it in this condition.

That’s because it is sensitive to root rot. As such, overwatering is its number one enemy.

This also means that you want to adjust how you water throughout the year. And, that using a regular schedule is not ideal.

The best way to water your alocasia macrorrhiza is to allow the top third of the soil to dry before you water it. This will prevent watering too often or when the soil is still fairly most.

In the fall and winter, scale back on watering frequency. The plant will go dormant in the winter. And as the weather gets colder it takes longer for soil to dry.

As such, it can be easy to overwater the plant during this time of the year. To stay on the safe side during the colder months, it is better to under water the plant. This is true if you live in cooler regions and it the plant sits in a shaded location.

Similarly, you want to consider what kind of water you use. Make sure to use room temperature or lukewarm water when watering the soil.

The plant’s roots are also sensitive to chemicals. As such, if the tap water is your area is hard, you want to allow it to sit at room temperature at least overnight to allow the chemicals to evaporate. Too much chlorine and fluoride, which are the most common elements added to tap water can build up in the soil.

This reduces soil quality and negatively affects your plant in the long term.

Last but not least, here are some signs of overwatering and underwatering you want to watch out for.

Overwatering. Too much water will cause moldy soil, increase the risk of root rot and yellow its older leaves. If left unmodified it will eventually kill your plant. Be more wary of this in shaded conditions.
Too little water isn’t as bad as overwatering. But, it affects the health of your plant as well. It will slow growth, turn leaves yellow and brown.

Soil

Since the alocasia macrorrhiza grows best in moist soil but is susceptible to overwatering, the best soil for the plant is one that retains just enough moisture to stay moist while being loose and well-draining.

It also likes rich, fertile soil. But, isn’t too fussy about the kind of soil you use or its pH.

Thus, you can use standard potting soil then add perlite or pumice to improve drainage. You can likewise use peat or coco coir to improve moisture retention if needed.

Fertilizing

Alocasia macrorrhiza need regular feeding. This allows it to sustain is size, large leaves and fast growth. Here, you can use regular houseplant fertilizer or a general purpose fertilizer. Both work. Make sure to dilute to half -strength when applying.

Feed the plant once every two weeks during the spring and summer. This is when the plant is actively growing. So, it will need the sustenance most at this time.

Cut back to once a month in the fall and winter as the plant goes into dormancy at the latter part of the year.

As always, water the soil when you fertilize. Plant food contains strong chemicals. And, when applied to dry soil the concentration will be too high for your plants, causing root burn and yellow leaves. Thus, adding water will reduce the concentration.

Pruning

Left untrimmed, your alocasia macrorrhiza will grow up to 12 to 15 feet covering a space of 6 to 8 feet wide. Its fast growth also means that you may need to prune it to control its size and shape.

Other than that, the only regular maintenance work you need to do is removing the dead or discolored foliage. These don’t look good on the plant.

And, they also cause the plant to use up resources on them. Trimming these off allow it to focus all its efforts on fresh and healthy parts.

Always use a sharp sterile part of cutting tools. You can use a large pair of scissors or pruning shears. It is likewise important to make precise, clean incisions. Jagged or blunted blades will increase the shock experienced by the plant.

Alocasia Macrorrhiza Propagation

source: wikiemedia commons

The alocasia macrorrhiza can be propagated from seed, stem cutting and division.

Of the three, dividing the tubers is the most effective way to producing more of this beautiful plant.

This process is done by separating the rhizomes. The best time to propagate the plant is during springtime.

Here’s how to do it:

Dig up the plant
Carefully take it out. Once you do, you’ll see many tubers extending from it under the ground.
Dust away excess soil.
Use a sharp, sterile pair of pruning shears and separate the tuber/s from the mother plant. how many you get will depend on how many new plants you want.
Replant the parent plant. Then, plant each of the tubers individually. You can put them into the ground or in containers.
Each of these divided tubers will grow into a copy of the parent plant.

Transplanting & Repotting Alocasia Macrorrhiza

As your alocasia macrorrhiza grows, it will one day outgrow its current container. This happens every 2 years or so. When this happens, it is time to repot it.

The best time to repot is during the spring. And, you want to go up one pot size up. Jumping too many sizes is never a good idea because it can stress out the plant and increase the risk of overwatering.

Watering the plant 24 to 48 hours ahead helps reduce transplant shock. It also helps soften the soil to make a pot bound plant easier to remove from the tight container.

Toxicity

If you’ve been to Hawaii, you’re probably familiar with alocasia macrorrhiza because you’ll see some there. But, the plant, which is also called Giant Taro, which is used to make poi, a popular native delicacy in Hawaii. The dish makes use of the plant’s roots.

However, it is very important to note that you need to cook the plant to make it edible. That’s because it contains calcium oxalates which are toxic to humans and animals.

Cooking breaks down these crystals to make them harmless when consumed.

On the other hand, eating any part of the plant raw will cause mouth, throat and digestive issues. So, keep it away from young children, dogs and cats.

Pests and Diseases

Your alocasia macrorrhiza can experience pests and disease. Although, it isn’t too prone to pests, you may still encounter some along the way. The most common attackers include spider mites, mealybugs, thrips and scale.

However, it is more susceptible to diseases, both bacterial and fungal. Overwatering can be a big problem when it comes to increasing the risk for these problems. As such, you want to avoid it. More light also helps water evaporate faster. Just as importantly, use well-draining soil.

Mold and root rot are common problems associated with too much moisture. It can also attract fungus gnats.

Frequently Asked Questions FAQs

How do you care for alocasia Macrorrhiza?

Alocasia Macrorrhiza care begins with medium to bright, indirect light. Keep it away from direct sunlight as the sun’s harsh rays can scorch its leaves. The Alocasia Macrorrhiza also likes moist soil that’s not damp or wet. Thus, allow the soil to dry between waterings.

Is alocasia Macrorrhiza fast growing?

The Alocasia Macrorrhiza is a fast growing plant. It grows the most during the warms months especially the summer. Therefore, make sure to give it sufficient light, water and fertilizer during its growing season to encourage growth and large foliage. The plant will eventually reach a size of 3 to 6 high and 2 to 4 feet wide with large spade-like leaves indoors.

Are alocasia Macrorrhiza rare?

Macrorrhiza Variegata Is a Very Rare Elephant Ear Plant

So, the Variegated Alocasia (Macrorrhiza Variegata) is a very rare elephant ear plant and is quite different from the typical. The incredibly large thickly sculpted glossy green leaves are held upright on dramatically rigid stems.

The Alocasia Macrorrhiza is not rare. You can easily get one from your local nursery or garden center. However, the variegated Alocasia Macrorrhiza, which is also known as the Macrorrhiza Variegata is very rare. This elephant ear features large green foliage with random white splotches making each leaf look different.

How big does alocasia macrorrhiza get?

The Alocasia Macrorrhiza will grow to between 12 to 15 feet tall and 6 to 10 feet wide when grown outdoors in your yard or garden. Indoors when kept in a pot it won’t get as big. The plant will usually reach 3 to 6 feet high and 2 to 4 feet wide.

Is alocasia Macrorrhiza poisonous if touched?

All parts of the Alocasia Macrorrhiza is toxic because the plant contains calcium oxalate crystals. However, the toxic part of the plant is its milky sap. The sap is released when the plant’s outer layer is broken. This means the Alocasia Macrorrhiza is safe to touch. But if you’re pruning, trimming or propagating where there’s cutting involved, then wear gloves and wash your hands after.

Is alocasia macrorrhiza indoor plant?

The Alocasia Macrorrhiza is a good indoor plant. It is native to the tropical parts of Asia. This makes the plant prefer moderate temperatures. Thus making the inside of the home perfect for it. That said, the Alocasia Macrorrhiza will grow well in warm climate conditions (USDA Zones 9 to 12). Keep it away from the cold and winter frost.