Have you ever wondered why a Monstera plant grows in such a distinctive way? The leaf holes, known as fenestrations, are very unusual and few other plants have developed them, but what purpose do they serve?
There are several theories about why these plants have developed holes in their leaves, including to reduce the risk of the leaf being torn in high winds, as a means of regulating temperature, or as a way of dealing with heavy rainfall. However, the most accepted explanation is that the leaves help the plant maximize its ability to capture sunlight.
Why Do Monstera Leaves Have Holes?
There is still some debate about the reason for the holes in the leaves, but the leading theory suggests that they help the Monstera to capture more light. Monstera plants grow in quite limited light because they are below the thick canopies of rainforests, and the sun rarely falls directly upon their leaves.
It is necessary for the Monstera to maximize every scrap of sun that comes through the canopy if it is to survive. As the leaves above the plant shift and sway, allowing the odd beam to pass through, the Monstera needs to have its leaves ready to capture it.
However, it is inefficient for the plant to grow dense leaves in every direction; they would quickly block each other out. It takes energy to grow and support a leaf, and if that leaf only captures a couple of rays a week because it’s mostly covered by other leaves, it isn’t justifying its use of these resources.
However, not having the leaf there at all isn’t a solution either, because the plant then misses rays that do fall in that spot.
The fenestrations are the answer because they allow the plant to cover a much greater area with its leaves, and stop the top leaves from blocking out the light that the bottom leaves can capture.
This theory might sound hard to believe, but a biologist at Indiana University in Bloomington has shown that it works. Christopher Muir demonstrated through mathematical equations that a leaf with slots has a much better chance of catching random sunlight beams than whole leaves do, even if they cover the same area.
The theory is further reinforced by the fact that when a Monstera is young, its leaves don’t tend to have fenestrations. In its natural environment, a young Monstera only has a few leaves and there are very few sunbeams for it to gather close to the rainforest floor, so the holes would not be useful.
However, as the Monstera matures and starts to climb, its upper leaves begin to capture more random rays and also block out the lower leaves. It is only at this point that the Monstera starts to develop the fenestrations because they become valuable.
It should be noted that this theory has not yet been proven; it is just accepted as the most likely explanation. The mathematical equations indicate it is very probable, but nobody has yet tested this on a real Monstera plant in its natural environment.
As science progresses, the theory may be put to the test, but for now, it is generally thought to be the best explanation for the Monstera’s holey leaves.
What Other Possible Reasons Are There For Monstera Leaves To Have Holes?
Although the above explanation is currently accepted as true, a few other suggestions have been given for the unusual leaf fenestrations, and it’s worth exploring these. They may be secondary advantages, or they may be unrelated, but they are still interesting.
To Reduce Wind Damage
Rainforests are not generally windy places, but having broad leaves can be a disadvantage if the winds do pick up, especially for plants that are high in the canopy, as a Monstera is likely to be.
Other plants have developed this as a survival strategy, so it is feasible to imagine that the Monstera has done the same. By growing splits and holes in its leaves, a Monstera ensures that wind can pass through them easily.
This reduces the stress on the leaves when wind speeds pick up, and may reduce the risk of breakages. It may also put less pressure on the stems and prevent them from snapping.
As A Means Of Temperature Regulation
A less likely theory was proposed by scientist Michael Madison, who suggested that the splits in the leaves help the plant deal with temperature issues. The splits would allow the leaves to cool, preventing them from overheating when left in the sun.
This theory is not widely accepted, however, as Monsteras usually grow in shady spots and do not cope well with direct sunlight. Their leaves tend to burn if they are exposed to sunlight for prolonged periods, which suggests that the splits do not really help with thermoregulation.
To Reduce Rain Damage
Rainforests often experience heavy downpours, sometimes heavy enough to be damaging to a plant’s foliage. This is particularly true of large foliage, which might get a lot of water hitting it at once. Delicate leaves could be torn by this sort of weather, so the theory arose that the Monstera’s fenestrations were a result of the rain.
By developing splits, the plant’s leaves could allow water to pass through, reducing the surface area that would be struck and the resulting shock wave. This might reduce the risk of damage to the leaves.
This theory may have some value, but given that Monstera leaves are reasonably tough and also bounce when struck, it is less convincing than Christopher Muir’s suggestion.
Even a very heavy downpour seems unlikely to do significant damage to a Monstera’s leaves, especially since these plants often grow up the trunks of other trees and would therefore be sheltered to some degree.
To Prevent Leaf Rotting
Another possible explanation for the splits also relates to the amount of rain these plants experience. If water is allowed to sit on a leaf for too long, it can cause rotting. This is particularly true if the leaf has been damaged.
It was thought for a while that the leaf splits prevented this because they stop water from sitting on the plant’s leaves. Again, this theory may hold some weight. However, a Monstera’s leaves are so glossy that water generally just rolls off them anyway.
Because the plant grows its leaves on long, flexible stalks, they can move and bounce when struck by water, and it seems unlikely that the Monstera would have too much of a problem with water sitting on its leaves.
In general, rain would roll off even a leaf without the holes, and because the leaves are so glossy, there’s minimal risk of water clinging and causing them to rot.
To Allow Water To Reach The Roots
This theory may carry more weight, although it has not been proven. Some scientists believe that having a net of umbrella-like, water-repellent foliage could cause water to be directed away from the plant’s roots, leaving them dry.
As rainwater falls and strikes the leaves, it rolls off to the sides of the plant, and because of the shape and angle of the leaf, it would naturally roll away from the plant’s main stem, and consequently fall further away from its root ball.
There are some suggestions that this could deprive the Monstera of water. By developing leaf fenestrations, the plant allowed water to pass through the leaves and fall around its roots (both subterranean and aerial).
It is possible that the Monstera enjoys this additional advantage as a result of having holes in its leaves, but given that rainforests are generally damp and humid places, it seems unlikely that rain rolling away would have caused a significant enough problem for the plant to change its foliage.
On the whole, water is not in short supply in a rainforest, and it doesn’t make sense for the Monstera to have changed its leaf structure solely for this reason. While the holey leaves may allow more water to land by the roots of the plant, this is unlikely to be the primary explanation.
Does The Amount Of Sunlight Effect The Fenestrations?
Monsteras actually develop more fenestrations when they are supplied with a good level of light, perhaps because this triggers them to grow more foliage, and there is more risk of it overlapping.
If your Monstera is not developing fenestrations or has very few, it may not be getting sufficient light. You don’t want to place it in the direct sun, because its leaves will burn, but you should put it somewhere with plenty of bright, indirect light.
This will encourage its leaves to develop those classic fenestrations, letting the light pass through to the lower foliage and maximizing your plant’s light-gathering efficiency.
How Can You Care For The Leaves?
You don’t need to do much for your Monstera’s impressive foliage, but it does help to regularly wipe the leaves down with a damp cloth. In an indoor environment, with no rain and wind to keep the leaves free from dust, they can gather a thin coating of debris, and this blocks out the sunlight and clogs up the leaf pores.
This reduces both the plant’s ability to photosynthesize and its capacity to respire and isn’t good for its overall health. It can also invite pests. You should therefore take steps to clean the leaves from time to time, especially if you live in a dusty environment.
You don’t need to use soap; just get a clean cloth, run it under the tap, and support the leaf you are cleaning with one hand while wiping it with the other.
You can also take this opportunity to inspect it for any signs of pests or diseases, and doing so may help to increase your Monstera’s life expectancy overall. Occasionally misting the foliage will also keep it fresh, clean, and healthy.
It has not yet been proven why the Monstera has leaf fenestrations and there is a multitude of theories, but the most likely and widely accepted one states that the holes help the plant gather sunlight more efficiently.
If your plant is developing lots of splits, it likely has a good amount of light and is flourishing. If it isn’t developing splits, try to increase its light levels and give it a dose of fertilizer to boost its growth.