How to Get Fenestrations (Splits & Holes) In Monstera Deliciosa Leaves

The split leaves of Monstera deliciosa is one of the things that sets it apart from other houseplants. They’re one of the few plants that readily produce fenestrated leaves indoors, though they do need certain conditions to grow them:

• Monstera need to be at least a couple of years old before they start producing splits in their leaves
• They need to be getting high levels of light
• They’re also more likely to produce split leaves if they’re climbing something.

A common alternative name to Monstera deliciosa is split-leaf Philodendron, but Monstera are not particularly closely related to Philodendrons, though they’re both in the aroids family.

A split-leaf Philodendron usually refers to a Thaumatophyllum bipinnatifidum, which is…also not a Philodendron. It also doesn’t have split leaves. Never mind. I’m sure whoever was in charge of naming it tried their best.

I don’t think any Philodendron species have fenestrated leaves, though Rhaphidophora, Monstera, and Epipremnum do.

ANYWAY

Why do Monstera deliciosa have splits/fenestrations in the leaves?

Bear in mind that research into aroids is practically non-existent because we don’t eat them or use them for medicine.

To allow light to the lower leaves

The current thinking is that the main advantage fenestrations gives Monstera deliciosa is the ability to climb a vertical tree whilst not shading out the lower leaves.

Most climbing aroids grow bigger leaves as they climb, and as a result, prevent light from getting to the lower leaves. This isn’t that big of a problem, because the newer leaves are so big they can do the work of several smaller, lower leaves.

The leaves that are shaded out by the newer ones quickly yellow and die.

Monstera deliciosa leaves also increase in size as they climb, but the holes and splits in the leaves mean that the lower leaves last longer, and the plant can harness more energy through photosynthesis.

To protect the plant from wind damage

Though wind damage isn’t too much of a concern in rainforests, because Monstera are protected by other trees, splits in the leaves help protect Monstera from gusty weather.

The wind can travel through the splits and holes without damaging them. This ability to withstand adverse weather conditions has helped Monstera grow prolifically in more exposed areas – not only invasive specimens in places like Florida but also those growing in places being deforested.

I think that the splits protect from wind damage and the holes allow light through, purely because my big Monstera still produces fenestrated leaves (because its leaves are huge and might snap in the wind if they were solid) but no holes, because when I propagated it, it no longer had any lower leaves.

To prevent standing water on the leaves

Contrary to popular belief, plants don’t like getting wet. When leaves get wet, the plant temporarily close its stomata and stops photosynthesising. Having holes in the leaves allows water to drain off quickly, so that the plant can get going again.

Keeping leaves dry also reduces the risk of bacterial infections.

Interestingly, aroids that have splits in their leaves seem to be the most efficient at adapting to new environments and accidentally becoming invasive – Golden Pothos and Monstera deliciosa are doing very well for themselves outside of their natural habitat. Plants with just holes in the leaves, like Monstera adansonii, don’t fair so well in the wild.

Whilst Monstera leaves probably split to allow for light to penetrate the canopy (or rather, that’s why that characteristic was passed on in the genes), the ability to tolerate high levels of wind and rain due to their leaf shape, helped them become successful in a variety of environments.

How long does it take for Monstera to get fenestrations?

Monstera deliciosa produce fenestrated leaves as a direct response to their environment. You could have a Monstera for 50 years and it won’t produce leaves with splits unless you give it a reason to.

Split leaves photosynthesise less efficiently than solid ones because they have less chlorophyll.

Monstera will only produce a less efficient leaf (i.e. a split one) if that will produce a net gain – i.e. growing a split leaf allows both the split leaf and the leaf below it to photosynthesize.

It’s true that Monstera don’t tend to produce split leaves until they’re at least two years old (ish) BUT it’s not an age thing so much as a size thing. Under the age of two, Monstera seem to concentrate more on quantity of leaf over size, so they grow a lot of leaves quickly. Once they start climbing, and their stem gets long, they start producing fenestrated leaves.

What are the levels of fenestration in Monstera?

There are a few different levels of fenestrations in Monstera, but there’s no obligation for every Monstera to go through all of them. Some Monstera progress extremely quickly through the levels and end up with double mid-rib holes. Others refuse to produce holes for years.

This depends on the cultivar (i.e. the genetics) of the plant and the environment it’s kept in.

There’s a lot of talk about large and small-form Monstera, and whilst they do have an impact on fenestrations, you can still grow MASSIVE small-form Monstera in good conditions.

It’s also worth noting that cuttings from small-form Monstera can develop into large-form plants. They’re NOT separate species, with different growth patterns – all Monstera deliciosa are climbers NOT crawlers.

All that stuff about large vs small internodal spaces and growth pattern differences is just an example of natural variations in plants that people make into a big thing in order to sell plants. The reason plants like Thai Constellation are all large form (i.e. size up quickly and get a lot of holes) is simply due to the genetics of the parent plant.

Level 1 – random splits

Level 2 – splits down one side

Level 3 – All splits, no holes

Level 4 – all splits, a single hole

Level 5 – all splits, several holes

Etc etc. I can’t give you a timeline, because Monstera growth rates vary a LOT and things like winter interfere with it. If the light gets lower, for example, your Monstera might produce smaller leaves.

Do Monstera leaves split as they grow?

No – Monstera leaves unfurl either with splits or without them, but an unsplit leaf won’t develop splits over time. When a new Monstera leaf unfurls, it will grow significantly, but nothing will change other than the shape.

NB if you try to add your own splits to your Monstera leaf, the plant will seal itself to avoid any diseases getting in, so the edges will go brown.

Do genetics affect the likelihood of a Monstera developing splits in the leaves?

Yes and no. Some Monstera deliciosa cultivars are more likely to develop highly fenestrated leaves than others. For example, if you want grow a highly fenestrated variegated Monstera, you’re better off buying a Thai Constellation over a Monstera variegata albo.

There’s no genetic difference between small and large form Monstera, so it’s possible to grow large small form Monstera, but not necessarily easier.

All Thai Constellations are large form, and, given the right care, will develop inner fenestrations. There is more variation when it comes to Monstera albo, so it’s the luck of the draw.

How to encourage fenestrations in Monstera

Wait until it’s old enough

I currently have a baby Monstera that’s about a year old (I got it in March, and it looked like a tissue culture baby). There’s no point expecting it to fenestrate until next year. Sure, it’s technically because it’s not old enough, but it’s more that…it doesn’t need to produce split leaves. All the leaves are around the same-ish height, and the taller leaves aren’t inhibiting light levels to the smaller ones.

Give it plenty of light

This is a biggy. You CAN keep Monstera deliciosa in low light, but you won’t get the big fenestrated leaves that they’re famous for, because there’s no point.

Monstera kept in low light won’t waste a leaf by putting splits in it – it needs all the chlorophyll it can get. Also, the petioles stretch towards the leaf, and then leaves weigh the petioles down, so the plants droops rather than climbs.

Fulfilling a Monstera deliciosa’s light requirements is the closest thing to a cheat code.

Increase the humidity

Monstera deliciosa aren’t particularly fussy when it comes to humidity levels BUT increasing the humidity can increase the leaf size and the chance of fenestrated leaves because it mimics the plant’s natural environment and makes up for things like occasion missed waterings.

Give it something to climb

As I’ve said (at least once, perhaps twice?) Monstera only produce fenestrated leaves if they need to, and you can, er, make them need to by growing them vertically. There are various ways of doing this. Mine grow well without any support other than it’s own aerial roots directed into the soil, but a moss pole can really help as well

There are plenty of people growing Monstera with huge, fenestrated leaves using coir poles or bamboo canes, but the reason that moss poles and directing aerial roots back into the soil works so well is that it creates a bigger subterranean root system. The bigger the root system is, the more stable the Monstera is and the more nutrients and water it has access to.

A Monstera that has a lot of resources and a means of growing up is highly likely to produce fenestrated leaves faster.

• How to stake your Monstera deliciosa

Water and fertilise it well

I mean, you need to care for your Monstera well if you want it to grow big leaves. As well as keeping it well-fed and hydrated, you need to make sure its root system is healthy, and it’s pest and disease free. These articles can help you with that:

• How to water Monstera
• How to fertilise Monstera
• The best soil for Monstera
• Pests and diseases of Monstera

Can Monstera stop producing split leaves?

Yes. If the environment around your Monstera changes, it might regress, and start producing less mature leaves. This often happens when you buy mature Monstera and then bring them home.

It’s normal for the first few new leaves to be fenestrated but then revert back to their immature form (the new leaves that is, the old leaves don’t magically lose their fenestrations).

You can try to increase the light and humidity using grow lights and humidifiers, but nurseries have conditions especially honed to mature aroids, and if your house doesn’t have the right conditions, it can be difficult to convince your Monstera to grow leaves with holes in.

You may also find that if you propagate a cutting, the new leaves won’t be as mature as they were when it as attached to the mother plant. Sometimes you just have to wait a couple of leaves for the mature leaves to start growing, but you might have to wait for it to mature again from scratch.

Do any other houseplants have split leaves?

Yes, a few other houseplants produce split leaves though often they’re trickier to convince to fenestrate:

• Rhaphidophora tetrasperma

It’s called mini Monstera for good reason, though they’re actually a different genus (though more closely related than they are to Philodendron). Rhaphidophora tetrasperma’s natural habitat is about as far away from Monstera deliciosa’s as it’s possible to get, but they have a very similar appearance.

• Epipremnum aureum

Commonly called Golden Pothos (though not actually a member of the Pothos genus), but also includes other Pothos, like marble queen and manjula. Though heartleaf Philodendron do get pretty big, they won’t fenestrate like Pothos.

• Monstera dubia

You rarely see the mature form of Monstera dubia, because they’re prized for their unusual shingling growth pattern, but when they grow up, they start growing like a regular climbing aroid.

• Epipremnum cebu blue

Usually grown as a hanging or trailing plant, but cebu blue develop fenestrations if you grow them up a pole. I have mine trailing because I like it though!

And that’s it for this article. Feel free to leaves questions and comments below.

Before you go, you might like these articles:

• How to get your Monstera to grow faster
• How big do Monstera get?
• Are Monstera epiphytes?