Elephant Ears Plants: Colocasia and Alocasia

Colocasia. Alocasia. Is it really necessary to know some of the differences between the two? Both are aptly called Elephant Ears for their impressively large shield- or heart-shaped leaves. Both are tropical looking and attractive. Is differentiating between the two really important?

I started out thinking that Colocasia and Alocasia plants were so similar, I could use their names almost interchangeably. I know both have become very much in-demand as houseplants over the past years. If I recall correctly, I believe I even read that certain varieties were “trending” in 2023… no surprise there, when I think of the dramatic look of most of these beauties.

But as I sought out more of these plants and dug into the topic of differences, I learned that the differentiation between Colocasia and Alocasia has implications for plant care. Would being able to discern one from the other help me to be sure I could keep my plants alive? Yes. (Pretty important, for sure.) But what some have presented as a manageable task of differentiating between the two genera actually poses quite a challenge for me, even though I am a person who has had the good fortune of seeing many plants. So, let me share what I have learned, and you can perhaps add to this information and more readily discern one genus from the other.

Differences in Typical Overall Growth Habits

Leaf Positioning

Let’s start by focusing on the "styling" of the two: Both Colocasia and Alocasia have leaves that are large in relation to their overall plant size. The leaves truly do look like the ears of elephants, with similarities to hearts or protective shields, as well. But plant-ponderers often say that Alocasias have upright foliage, while Colocasias have stems that bend and leaves that face outward. Problem is, this rule of thumb is "all thumbs"... pretty clumsy and inaccurate.

Some of the Alocasias do indeed hold their leaves upright (points of the hearts, for example, pointing skyward) while others hold their leaves horizontally (for instance, like shields being held flat and parallel to the ground). And several of the Colocasia varieties do let their leaves bend even more than do the leaves of the Alocasias, greeting admirers face-forward.

But using leaf positioning (upward pointing versus outward facing leaves) as a means of differentiating between the two genera results in finding all sorts of exceptions to this "rule". For example, the Alocasia known as Cuprea 'Red Secret' looks out to its crowd of admirers, displaying its dark leaves with their waxy sheen. Alocasia 'Polly', known as the African Mask Plant, also shows its serrated leaf "masks" face-on. These and countless other exceptions to the leaf positioning rule exist.

But what seems to hold true, at least among the varieties of these plants that I have seen, is that the stems on Colocasias attach to the leaves well within the leaf margins. Sometimes they attach close to the middle of the leaf. This tends to tip the leaves downward and outward. On the other hand, the Alocasia stems I have seen are attached to the leaves at the leaf margins and trail along the lengths of the leaves, strong and supportive. This can cause some, but not all Alocasias, to point their leaves toward the sky. So, I understood why the rule of thumb came to exist, but I found myself lacking confidence in using it.

Textural and Other Differences

So what about leaf texture? I knew that some of the best-loved Colocasias have beautifully corrugated leaves, with matte or glossy foliage rippling here and there. But to complicate things, this also applies to some of the Alocasia varieties. Textural differences are not much of a help in differentiating one genus from the other.

It seems that the better way of differentiating may be to inspect the undersides of the leaves to look for waxy glands. These are part of the make-up of the Alocasias but not the Colocasias. The glands show up as prominent veins.

In the end, I must say that I love both Colocasia and Alocasia plants, and I am ever more thankful for helpful plant identification tags, reliable labeling, and signage. While I know much more about these plants than I did before, I suspect I will continue to rely on others to confirm my suspicions about which plant is which. But I know for sure that I am drawn especially to those plants within the genus that have unusual patterning and outrageously beautiful coloration. These bold and dramatic selections seem rare, tropical, and just right for adding to an indoor houseplant display.

Difference in Care Requirements

I might not have a true preference in terms of these two genera. But I now realize it is quite important to know which type of plant I have in hand. This is due to the fact that Colocasia and Alocasia have different growing requirements. Colocasia grows beautifully in soggy soils, to the point of bordering on being an aquatic plant. Alocasia is more particular about needing good moisture but no wet feet. Moreover, an Alocasia requires lighter and less frequent watering in winter, while a Colocasia can handle even the wettest growing medium year-round.

In terms of light, Alocasia prefers a dappled light and some shade. Colocasia is more comfortable in consistently bright-light conditions. Both can grow large and full outdoors if the climate is right (consistently warm and humid), and both thrive and look impressive as houseplants if placed in the right spot in the home and away from pets. (Oxalate crystals are present in these plants, so it is unsafe to let pets nibble them.) Personally, for the conditions in my home, I think both are beautiful houseplants.

Summing Up

So, when you next hear of the “elephant in the room”, realize the big reveal may be around a houseplant, Colocasia or Alocasia. Different but equally nice, these plants are in demand for a reason. Try to identify them, but then get some help along the way to confirm what you have in hand. After that, and once you know their care requirements, you can simply enjoy them. I know I do.