What Is Fenestration in Plants and How to Encourage It?

Fenestration in plants refers to the natural holes and splits that develop in the leaves of certain species, most famously the Monstera genus, commonly sold as the “Swiss cheese plant.” These openings are not damage or disease; they are a genetically programmed feature that forms during early leaf development through deliberate cell death. For houseplant growers hoping to see those iconic perforated leaves, the key factors are light, maturity, and overall plant health, though the underlying biology is far more interesting than most care guides suggest.

What Fenestration Actually Is

The word “fenestration” comes from the Latin fenestra, meaning window, and it describes any natural opening in a leaf blade that creates a hole surrounded by intact tissue. These are not tears caused by wind or herbivores. They form as part of the leaf’s built-in developmental program, appearing in predictable locations on the leaf surface while the leaf is still tightly furled inside the bud.

Fenestration takes several forms depending on the species. In Monstera deliciosa, the most well-known example, young leaves may develop oval holes scattered across the interior of the blade. As the plant matures, perforations can also appear near the leaf margin, and when the thin bridges of marginal tissue tear as the leaf expands, the result is a deeply split, almost palm-like shape.¹ The holes and the splits are really the same phenomenon expressed in different positions on the leaf.

How the Holes Form

Fenestrations are carved out through programmed cell death, a process in which specific clusters of cells essentially self-destruct on cue. This is not random decay. In Monstera obliqua, researchers have documented that at each future perforation site, a discrete group of cells simultaneously undergoes DNA fragmentation and cellular breakdown while the neighboring cells remain perfectly healthy and continue developing normally.² The dying cells show condensed, misshapen nuclei, disrupted internal compartments, and shrunken contents, all hallmarks of a controlled demolition rather than accidental damage.

Crucially, the cell walls at the perforation site stay intact even as the cells inside die. The tiny disk of dead tissue only separates from the surrounding healthy leaf once the blade starts expanding and physically stretches the perforation open. So the hole you eventually see on a mature unfurled leaf was already mapped out when the leaf was a fraction of its final size, still rolled up inside the growing tip.

Why Plants Evolved Holes in Their Leaves

Putting holes in a photosynthetic surface seems counterproductive. Less leaf area means fewer cells capturing light, which should mean less energy for the plant. This paradox puzzled botanists for a long time, and several explanations have been floated over the decades, from better wind resistance to improved water drainage. The most compelling current hypothesis focuses on how Monstera species actually encounter light in the wild.

Monstera are secondary hemiepiphytes, meaning they germinate on the forest floor and climb upward along tree trunks into the canopy. For much of their lives, they sit in the deep shade of tropical rainforest understories, where direct sunlight only arrives as brief, unpredictable flashes called sunflecks as the canopy above sways. A modeling study published in The American Naturalist demonstrated that fenestrated leaves can reduce the variance in a plant’s growth rate in this kind of flickering light environment, and that lower growth variance translates into higher long-term fitness.³ In plain terms, a holey leaf spread over a wider area has a better chance of intercepting at least some of those random sunflecks than a smaller, solid leaf with the same total tissue area would.

Think of it like casting a wider net with the same amount of rope. You catch fewer items per square inch of net, but you cover more ground, so on any given toss your haul is more consistent. For a plant living on unpredictable light, that consistency matters more than raw photosynthetic efficiency on a sunny day.

Why Young Monstera Leaves Have No Holes

If you have ever bought a small Monstera, you probably noticed that its first leaves are solid, heart-shaped, and entirely unfenestrated. This is not a sign of poor health or bad care. It is a developmental stage called heteroblasty, where a plant produces dramatically different leaf shapes at different points in its life.

The growth-variance hypothesis mentioned above actually predicts this. A tiny seedling on the forest floor receives such uniformly low light that there is no flickering patchwork of sunflecks to intercept. Without that unpredictable light environment, the advantage of spreading leaf area wide through fenestrations does not exist, and the plant is better off building solid leaves that maximize photosynthesis per unit of tissue.³ As the plant climbs and reaches higher, brighter, more variable light conditions, fenestrations start to appear and gradually become more elaborate. The transition from solid to split leaves is not a switch that flips; it is a gradient tied to the plant’s size, age, and light exposure.

The same logic explains why co-occurring juvenile tree species in the same tropical forest do not produce fenestrated leaves either. They are growing upward through the same dim understory, but as trees, their eventual strategy is to build a full canopy crown overhead, not to spread holey leaves sideways in dappled shade.

How Light Exposure Shapes Fenestration

Even on a single mature Monstera plant, not all leaves fenestrate equally. A 2025 study of Monstera deliciosa growing in Costa Rica compared leaves in direct sun with leaves in shade on the same plants. Sun-exposed leaves had a fenestrated area averaging about 76 square centimeters, roughly 4.7 percent of the effective leaf area, while shade leaves averaged just 28 square centimeters of fenestration, or about 1.9 percent of effective leaf area.⁴ Sun leaves also had higher stomatal density, meaning more of the tiny pores that handle gas exchange, suggesting the leaf’s entire architecture adapts to higher light, not just the holes.

This is an important finding for indoor growers because it confirms that light is not just a prerequisite for general plant health. It is directly tied to how much fenestration a leaf develops. A Monstera sitting in a dim corner may survive and even grow, but its new leaves will tend to be smaller, more solid, and less dramatically perforated than those on a plant getting strong indirect light.

How to Encourage Fenestration on Your Monstera

Understanding the biology above translates into practical advice. Fenestration is not something you can force artificially, but you can create conditions where the plant is most likely to express its full genetic potential for hole production.

Give it bright indirect light. This is the single most important factor. The field data from Costa Rica show that more light correlates with more fenestrated area per leaf. A spot near a large east- or south-facing window, or a few feet back from a west-facing one, usually works well. Direct midday sun through glass can scorch the leaves, but erring on the side of more light rather than less will generally push fenestration forward.
Let it mature. No amount of perfect care will produce fenestrated leaves on a very young plant. Monstera typically need to be at least two to three years old, with stems thick enough to support larger leaves, before fenestration begins. Patience is unavoidable here.
Provide a climbing support. In the wild, Monstera climb tree trunks. A moss pole, coir pole, or even a plank of rough wood gives the aerial roots something to grip, which encourages the plant to produce larger, more mature leaves rather than trailing, juvenile-type growth. The larger the leaves, the more room for fenestrations to develop.
Keep roots healthy. Root health underpins everything. A rootbound plant or one sitting in waterlogged soil cannot allocate energy to building elaborate new leaves. Well-draining soil and a pot with adequate drainage matter more than any specialized fertilizer regimen.
Maintain adequate humidity. Monstera evolved in humid tropical understories. While they tolerate normal household humidity reasonably well, consistently dry air can stress the plant enough to reduce new leaf size. A humidifier or a pebble tray can help in very dry climates, though this is secondary to light and maturity.

One thing that does not work is cutting holes in the leaves yourself. This occasionally circulates as a tip online, but manual holes will not trigger the plant to produce fenestrated leaves in the future. The perforation pattern is determined during early leaf development inside the bud, long before the leaf unfurls. Cutting a mature leaf just creates a wound that the plant has to heal.

What Happens When Light Drops

A question that comes up often among growers is whether a Monstera that has been producing fenestrated leaves can “lose” its fenestrations. The answer is that existing holes never close, since the tissue there is gone for good. But if you move a plant from a bright spot into a significantly darker one, its new leaves may come out smaller and with fewer or no fenestrations. The plant essentially reverts toward its juvenile-type growth in response to the lower light. This is consistent with the field observations showing shade leaves have roughly half the fenestrated area of sun leaves on the same individual plant.⁴

If you want your plant to keep producing progressively more fenestrated leaves, maintaining or gradually increasing light exposure over time is the most reliable approach. Moving a plant outdoors for the summer in temperate climates, where it can receive filtered sunlight, often produces a burst of larger, more elaborately split leaves compared to indoor growth during the same period.

Fenestration in Other Plants

Monstera gets most of the attention, but fenestration is not unique to one genus. Within the Araceae family alone, five genera besides Monstera produce perforated leaves through the same mechanism of localized programmed cell death.¹ And in an entirely unrelated plant family, the aquatic lace plant (Aponogeton madagascariensis) produces strikingly perforated leaves through a parallel process.

In the lace plant, perforations form in the spaces between the longitudinal and transverse veins, in regions called areoles. Cell death begins in the center of each areole and spreads outward toward the veins, creating a gradient of dying cells radiating from the middle.⁵ As the cells die, their walls are actively degraded: the outer cuticle erodes first, then the structural components of the wall dissolve, leaving loose fibrous networks that eventually break apart as the perforation opens up.⁶

This is a notable contrast to Monstera, where the cell walls at perforation sites stay intact and the dead tissue disk simply separates mechanically as the leaf stretches. The lace plant actually dissolves its cell walls chemically, which produces a much more delicate, lace-like skeleton of veins with open panels between them. The end result looks entirely different from a Monstera leaf, yet both achieve fenestration through programmed cell death. Researchers consider the lace plant a valuable model system for studying this process because its perforations form so predictably and the developmental stages are easy to observe.⁷

Common Misconceptions About Fenestration

Several persistent myths circulate in the houseplant community about what causes or prevents fenestrations, and they are worth addressing directly.

The first is that fenestration is caused by the plant “reaching for light.” The idea here is that holes develop because the leaf is starved of light and is trying to let light through to lower leaves. This gets the relationship backwards. Fenestrations are more extensive in higher-light conditions, not in darker ones. The evolutionary advantage is about spreading a given amount of leaf tissue across more area to catch scattered sunflecks, not about creating skylights for other leaves.

A second misconception is that specific fertilizers or supplements can trigger fenestration. While a well-fed plant will grow faster and produce larger leaves, no particular nutrient ratio has been shown to independently promote hole formation. The fenestration program is genetically encoded and its expression is tied to maturity and light. A plant that is too young or too light-deprived will not fenestrate regardless of what you feed it.

A third is that all Monstera species fenestrate in the same way. In reality, species within the genus vary considerably. Monstera deliciosa tends to develop both interior holes and marginal splits with maturity. Monstera adansonii (often sold as the “Swiss cheese vine”) produces abundant interior holes even at relatively small sizes but rarely develops the dramatic marginal splits. Monstera obliqua, which is rare and frequently mislabeled in the trade, can have leaves that are more hole than leaf, with the tissue reduced to thin ribbons between perforations. Each species has its own genetic parameters for when, where, and how extensively perforations form.

The Physical Side of Growing a Perforated Leaf

From a purely structural standpoint, putting holes in a flat surface changes how that surface responds to mechanical forces. Wind, rain impact, and the leaf’s own weight all interact differently with a fenestrated blade than with a solid one. Researchers working on the mechanics of leaf growth have noted that the fenestration process in Monstera deliciosa presents a compelling case for studying how two-dimensional biological patterns handle internal stresses during expansion.⁸ A solid leaf that grows unevenly can buckle and ripple. A fenestrated leaf can potentially release internal elastic energy through the perforations, allowing the remaining tissue to lie flatter.

For the plant in the wild, flatter leaves in the understory may be functionally important. A leaf that curls or ripples can self-shade parts of its own surface, reducing photosynthetic efficiency in an environment where every photon counts. Whether fenestration evolved partly to solve this mechanical problem, or whether the flatter growth is just a fortunate side effect, remains an open question. But the physics is real: holes change how a growing sheet of tissue distributes stress, and the plant’s development seems to account for that.

For indoor growers, the practical takeaway is modest but worth knowing. A heavily fenestrated Monstera leaf is not structurally weaker than a solid one in any way that matters indoors. The veins that frame each perforation act like structural beams, and the leaf’s overall shape is engineered by evolution to be mechanically sound. You do not need to worry about supporting or protecting fenestrated leaves any differently than intact ones.

1
Botanical Journal of the Linnean Society. Alternative modes of leaf dissection in monocotyledons
2
Planta. Programmed cell death and leaf morphogenesis in Monstera obliqua (Araceae)
3
PubMed. How did the swiss cheese plant get its holes?
4
Revista de Biología Tropical. Phenotypic differences in sun and shade leaves of Monstera deliciosa (Araceae)
5
PubMed Central. The pathway of cell dismantling during programmed cell death in lace plant (Aponogeton madagascariensis) leaves
6
PubMed. Cell wall degradation and modification during programmed cell death in lace plant, Aponogeton madagascariensis (Aponogetonaceae)
7
PubMed Central. A comparison of induced and developmental cell death morphologies in lace plant (Aponogeton madagascariensis) leaves
8
PubMed Central. Minimizing the Elastic Energy of Growing Leaves by Conformal Mapping