If you’ve spent any time in the Monstera community, you’ve probably come across the names “borsigiana” and “deliciosa” being used as if they refer to two completely different plants. You may have heard growers debate large form versus small form, argue about whether your variegated plant is the “right” type, or confidently claim they can spot the difference at a glance.
Here’s the truth: it’s more nuanced than most of those conversations suggest and one of the most commonly repeated identifiers is far less reliable than people think.
In this guide, we’ll clear up the naming confusion once and for all, walk through all the ways people try to tell large form from small form, explain which methods are actually reliable, and share the one definitive trick that makes identification fast, clear, and possible even from a single cutting. We’ll also cover Thai Constellation growth timelines, aerial root propagation, and what to do when new leaves come out damaged. Let’s get into it.
1. First Things First: “Borsigiana” Is Not a Separate Species
Before anything else, let’s clear up the most persistent misconception in this topic: Monstera borsigiana and Monstera deliciosa are not two different species. Borsigiana is an old name — a synonym — that is no longer recognised as a distinct botanical classification. Both names refer to the same plant: Monstera deliciosa.
The distinction that actually matters is not borsigiana versus deliciosa. It is a small form versus a large form — two growth forms within the single species Monstera deliciosa.
In informal plant community usage, some growers still use “borsigiana” to refer to what is now understood as the small form of Monstera deliciosa. Large form is simply called large form. Going forward in this guide, we’ll use the accurate terminology: small form and large form.
With that settled, does it actually matter which form you have? In most everyday care situations, not really. Both forms are beautiful, both are cared for identically, and both can thrive in similar conditions. The one area where it can make a practical difference is support: small form plants in low light conditions can develop very long internodal spacing — sometimes 20 cm (around 8 inches) or more between each leaf — which means they may need a moss pole or other support more urgently than compact-growing large form plants.
Large Form vs. Small Form: Quick Comparison
|
Feature
|
Small Form
|
Large Form
|
| Old informal name | Borsigiana | Large form (no alternative name) |
|
Availability
|
Very widely available; most common in nurseries and garden centres
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Less common; harder to find in standard retail
|
| Internodal spacing | Can be long (20 cm / 8 in+) especially in low light | Generally shorter and more compact |
|
Leaf shape (general)
|
Slightly more oval
|
Slightly rounder
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| Variegation type (general) | More marbled/mottled variegation | More sectoral (clear patches) |
|
Petiolar sheath — THE KEY DIFFERENCE
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Covers more than half (often 2/3 or more) of the petiole
|
Covers less than half (roughly 1/3) of the petiole
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| Petiole tip (pointed vs flat) | Usually no distinct pointed tip at base | Often has a visible pointed tip at the base of the petiole |
|
Growth rate
|
Standard; responds well to good light
|
Generally slower; harder to grow at scale
|
| Thai Constellation form | Not available as Thai Constellation | All Thai Constellation plants are large form |
2. The Unreliable Methods (And Why They Fall Short)
Growers have been debating how to tell large form from small form for years, and several commonly repeated methods have circulated widely. Let’s go through them honestly — because most of them are far less clear-cut than their proponents suggest.
Leaf Shape: Oval vs. Round
The popular wisdom says large form leaves are rounder in shape, while small form leaves are more oval or elongated. In theory, this distinction exists. In practice, it is frustratingly difficult to apply consistently — especially when comparing plants of different ages, sizes, or growing conditions. Leaf shape varies considerably even between leaves on the same plant. Without placing a verified large form and verified small form side by side, most growers find this method nearly impossible to apply reliably. Treat it as a supporting clue at best, not a primary identifier.
Variegation Type: Marbled vs. Sectoral
Another commonly cited difference: variegated small-form plants are said to display more marbled or mottled variegation (speckled and blended white or yellow mixed into the green), while large-form variegated plants are said to show more sectoral variegation (clear, distinct patches of white or yellow against green, with cleaner boundaries).
Like leaf shape, this distinction has some basis in reality — but it’s also highly variable. Variegation patterns are influenced by light levels, growing conditions, the specific mutation involved, and the age of the plant.
The same plant can display different variegation patterns on different leaves depending on conditions. Using the variegation type as a primary identification method leads to a lot of uncertainty and incorrect conclusions. It can support a hunch — but it shouldn’t be relied upon alone.
Internodal Spacing: Gap Between Nodes
This is perhaps the most widely cited difference: small form plants are said to have longer gaps between nodes (the points on the stem where each leaf and petiole grows), while large form plants grow with shorter, more compact internodal spacing.
The problem? Internodal spacing is heavily influenced by light. A small form plant growing in bright light will produce tight, compact internodes — sometimes just 1–2 cm apart — that look very similar to large form growth. Conversely, a small form in low light will stretch dramatically, producing internodes of 20 cm or more as the plant reaches for light. The plant’s form hasn’t changed — only its environment.
This means internodal spacing can point you in a direction, but it absolutely cannot confirm form on its own. A plant with tight internodes might simply be a small form with excellent light, not necessarily a large form. Use this as context, not confirmation.
3. The Petiolar Sheath: The One Reliable Identifier
After years of uncertainty with the methods above, plant growers have settled on one clear, consistent, and reliable way to distinguish large form from small form Monstera deliciosa — and once you understand it, it takes only seconds to apply.
It’s the petiolar sheath.
What Is a Petiole and a Petiolar Sheath?
Let’s define terms quickly:
- The petiole is the slender stalk that attaches a leaf to the plant’s main stem. It forms the connection between the stem and the leaf blade and is typically a long, curved structure that supports the leaf.
- When a new leaf emerges on a Monstera, it grows out from the petiole of the previous leaf. As it does, it leaves behind a papery, sheath-like remnant wrapped around the base of that petiole — this is called the petiolar sheath.
- Over time, the petiolar sheath dries out and turns brown, but its position on the petiole remains clearly visible even on older growth.
The petiole sheath is present on every Monstera plant — young, old, variegated, green, cutting, or established plant. And its relative length on the petiole is what tells you definitively whether you have small form or large form.
How to Use the Petiolar Sheath to Identify Form?
Here is the test:
- Find a mature petiole on your plant (not the very newest leaf — a leaf that has been fully open for at least a few weeks works best)
- Identify where the petiole begins (at the stem) and where it ends (at the leaf blade)
- Look at the petiolar sheath — the papery remnant wrapped around the lower portion of the petiole.
- Estimate what proportion of the petiole the sheath covers.
Now apply the rule:
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Petiolar Sheath Coverage
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Form
|
| Covers MORE than half the petiole (often 2/3 or more) | Small form |
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Covers LESS than half the petiole (roughly 1/3 or less)
|
Large form
|
That’s it. Once you’ve seen this difference clearly even once, it becomes immediately obvious. No measuring, no guessing at leaf shape, no waiting for variegation patterns to develop. You look at the petiolar sheath, you see how high it reaches, and you know.
This method works on established plants, on single-leaf cuttings, and even on juvenile plants — as long as you look at a mature leaf rather than a brand-new one just emerging from its sheath. Because the sheath itself is what you’re examining, very new leaves are harder to assess (they’re still emerging). Give it a few weeks to open fully, and the sheath position becomes easy to read.
A Secondary Clue: The Petiole Tip
Some growers have also noted a secondary structural difference at the base of the petiole: large-form plants often display a visible pointed or winged tip at the very base of the petiole, near where it meets the stem. Small form petioles typically don’t have this pronounced tip.
This characteristic is less consistent than the petiolar sheath length, but it’s worth checking as a supporting indicator when you’re comparing plants. If both the sheath coverage and the petiole tip point in the same direction, your identification is more confident.
Important Caveat: Use Mature Leaves
One important note from experienced growers, the petiolar sheath method is most reliable on mature leaves, not on the first one or two leaves of a cutting or very young plant.
On brand-new growth, the sheath hasn’t fully developed its characteristic position, and newer leaves still emerging from the sheath can make it harder to read accurately. For the clearest result, look at a leaf that has been fully open for several weeks and where the sheath has had time to dry and settle into its natural position. On established plants with several mature leaves, the petiolar sheath difference is typically unmistakable.
4. Large Form vs. Small Form in Practice: What to Expect
Small Form: The One You Probably Have
Small form Monstera deliciosa is by far the most common form available in nurseries, garden centres, and the general houseplant trade — particularly in Europe and North America. The vast majority of variegated Monsteras sold commercially (including most white-variegated plants) are small form.
Small-form plants grow well in a wide range of conditions. In bright light, they produce tight, compact growth with short internodes and develop impressive fenestrations as they mature. In lower light, they stretch considerably, producing longer internodes as the plant reaches toward the light source. If your small form plant has very long internodes, increasing its light level will compact the growth significantly.
Small-form plants are generally more forgiving, faster-growing, and easier to propagate than large-form plants, which is a big part of why they dominate the commercial market.
Large Form: Rarer and Slower
Large form Monstera deliciosa is significantly harder to find outside of specialist collectors and dedicated plant shops. Non-variegated large-form plants, in particular, are genuinely difficult to source. The most accessible large form plants for most growers are Thai Constellation Monsteras — which are always large form — and certain other cultivated variegated forms.
Large form plants tend to grow more slowly than small-form plants and can be more demanding in terms of the conditions needed to produce their best growth. In ideal conditions — strong light, warm temperatures, high humidity, good support — large form plants produce impressively round, dramatic leaves with generous fenestrations. However, they are more patient-testing than small form, particularly when it comes to producing new leaves.
Thai Constellation Growth: What to Expect
Since Thai Constellation is always a large form, and one of the most popular large form plants available, it’s worth addressing the question that many growers have: how long does it actually take for a Thai Constellation to grow a new leaf?
The honest answer is: it varies enormously, and long gaps between leaves are completely normal. Plant tracking data from experienced growers suggests a highly variable range:
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Interval Between Leaves
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Notes
|
| 6 weeks | The fastest recorded — exceptional conditions required |
|
1.5 months
|
Fast growth; typically during summer with good light
|
| 4–5 months | Common timeframe; normal for most household conditions |
|
6–8 months
|
Normal for winter periods or lower light conditions
|
| Up to 8 months | Possible during dormant or stressed periods — not a sign of failure |
If your Thai Constellation hasn’t produced a new leaf for several months, that is almost certainly not a problem with your care — it is simply how this plant grows. The most effective way to speed up leaf production is to increase light. More light means more energy, which directly translates to faster growth. A south-facing window (with a light shade cloth in peak summer if needed) or a strong grow light running 12+ hours a day will produce noticeably faster results than lower-light conditions.
One other useful note: keeping a simple plant tracking journal — even just noting the date each new leaf opens — makes it much easier to understand your individual plant’s rhythm. What feels like “nothing is happening” often turns out to be a completely normal growth pattern when you see the dates written out.
5. Practical Tips for Monstera Deliciosa Owners
Some pro tips you need to know.
Light: How Much Is Enough?
Monstera deliciosa is more light-tolerant than many people assume. Both forms thrive in bright indirect light, and they can handle more direct sun than many tropical houseplants — particularly morning or late afternoon sun, which is less intense than midday rays.
Signs your plant is getting too much direct sun:
- Leaves start looking washed-out or lighter green — this is the first sign of bleaching.
- Yellowing concentrated at the tops of leaves.
- Brown, burnt patches on the leaf surface.
In practice, many experienced growers find that Monsteras handle high light levels very well — better than many other popular houseplants. If your goal is dark, rich green leaves, full sun isn’t the right approach. But if your goal is faster growth and more fenestration, erring on the side of more light (with some afternoon shading in peak summer) will produce better results than keeping the plant in lower light conditions.
When to Repot: Does a New Leaf Change the Timing?
A common question from Monstera owners is whether it’s safe to repot when the plant is currently pushing out a new leaf. The short answer is yes — repotting while a new leaf is unfurling won’t kill the plant. However, there are good reasons to wait if the timing allows:
- A new leaf that hasn’t hardened off fully is more delicate and more susceptible to physical damage during repotting.
- Repotting creates some level of root disturbance, which can divert the plant’s energy and potentially slow the development of the emerging leaf.
- If you’re prone to being a bit rough with your plants during repotting, waiting until the leaf has fully hardened reduces the risk of accidental damage.
If repotting genuinely can’t wait — the plant is severely root-bound, the pot is breaking, or another urgent issue demands action — go ahead and repot. Just handle the new leaf with extra care and expect it to take slightly longer to reach full size. If timing is flexible, waiting until the new leaf is fully open and hardened is the lower-risk approach.
Aerial Roots and Propagation
Monstera aerial roots — those thick, rope-like structures that grow from the stem — are often misunderstood. Here’s what to know about using them for propagation:
- Aerial roots can absolutely be used in propagation. When placed in water or soil, they develop into true soil roots.
- Occasionally, an aerial root may rot when placed in water or soil — but this doesn’t mean propagation has failed. Monsteras can produce new roots not just from nodes but from other points along the stem.
- A cutting with at least a small aerial root or root nub has a much higher chance of successful propagation than a bare cutting with nothing. The root gives the plant a head start before it can produce new roots from scratch.
- If possible, guide aerial roots into the soil while the plant is still in the pot. By the time you take a cutting, it will already have an established root system attached.
- For cuttings with no roots at all, the risk is higher — the plant must root before it rots. Using a small amount of rooting hormone and keeping the cutting in water or a moist medium in a bright, warm spot maximises the chances of success.
The golden rule of propagation: get a cutting with at least a small root or root nub, place it in the right conditions, and give it time. Patience is the most important ingredient.
New Leaves Coming Out Damaged: What Does It Mean?
It can be alarming to watch a new leaf emerge crumpled, torn, or damaged-looking. Before jumping to conclusions, consider these possibilities:
- Physical emergence damage: On young cuttings, especially the first leaf or two to emerge can look quite rough. The plant works hard to push that new leaf out, and it sometimes shows. In most cases, the following leaves emerge more cleanly as the plant establishes itself
- Pests — particularly thrips: Thrips are small, fast-moving insects that feed on new growth before it hardens. If multiple new leaves are coming out damaged, scarred, or with silvery streaks, check the undersides of leaves and any unfurling growth carefully for pest activity.
- Low humidity: Very dry air can cause new leaves to develop with brown, crispy edges or damaged tips as they unfurl.
- Physical obstruction: Sometimes a new leaf simply gets tangled or squeezed by a moss pole, stake, or neighbouring stem as it tries to unfurl.
One damaged first leaf on a new cutting is usually nothing to worry about. Persistent damage on every new leaf, or damage combined with visible spotting or discolouration, warrants a closer pest inspection.
6. Summary: How to Tell Large Form from Small Form
Here is the definitive, step-by-step process for identifying whether your Monstera deliciosa is large form or small form:
|
Step
|
What to Do
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What It Tells You
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| 1 | Ignore the name ‘borsigiana’ | It’s not a separate species — only small form and large form matter |
| 2 |
Find a mature petiole (a leaf that has been fully open for several weeks)
|
Newer leaves give less reliable readings
|
| 3 | Locate the petiolar sheath (the papery remnant wrapped around the lower petiole) | This is your primary identification tool |
| 4 |
Estimate: does the sheath cover more or less than half the petiole?
|
More than half = small form. Less than half = large form
|
| 5 | Check for a pointed tip at the petiole base (secondary clue) | Present = likely large form. Absent = likely small form |
| 6 |
Use internodal spacing and leaf shape as supporting context only
|
These vary with light conditions and cannot confirm form alone
|
The petiolar sheath method is the most reliable single identifier available for distinguishing Monstera deliciosa forms — and the best part is that it works on a single cutting, on young plants, and on mature established plants alike. Once you’ve seen the difference clearly, it takes only a second to assess.
Frequently Asked Questions
Is Monstera borsigiana a separate species from Monstera deliciosa?
No. Borsigiana is just an old synonym for deliciosa. The only real distinction is small form vs. large form.
Does it matter which form I have for care purposes?
Not really. Both forms need the same care. The main difference is that a small form can get very leggy in low light and may need a moss pole sooner.
Are all Thai Constellation Monsteras large form?
Yes. Every Thai Constellation is large form, without exception.
Can I use the petiolar sheath method on a single cutting?
Yes — as long as the cutting has at least one mature, fully-opened leaf. Avoid reading very new or still-emerging leaves.
Why does my small form plant have tight internodes?
It’s getting enough light. Good light compresses internodal spacing on small form plants significantly, which is why internodes alone can’t confirm form.
My Monstera’s new leaf came out damaged. Should I be worried?
On a new cutting, one damaged leaf is normal. On an established plant, check for thrips or low humidity if damage keeps recurring.
How can I tell a large form from a small form on a variegated plant?
Same method — check the petiolar sheath on a mature leaf. Variegation type is not a reliable identifier.
Final Thoughts: The Method That Changes Everything
The large form vs. small form debate has caused a lot of confusion in the Monstera community for a long time — largely because most of the commonly cited identification methods are unreliable, variable, or require years of experience to apply consistently.
The petiolar sheath method cuts through all of that. It is fast, it is visual, it is applicable to cuttings and established plants alike, and once you know what you’re looking for, it is immediately clear. More than half of the petiole covered — small form. Less than half — large form. That’s the whole test.
Beyond identification, both forms of Monstera deliciosa are genuinely wonderful plants. Small form is accessible, fast-growing, and widely available. Large form — particularly the spectacular Thai Constellation and other variegated cultivars — rewards patience with some of the most dramatic foliage in the houseplant world. Whichever form you have, knowing what it is helps you set the right expectations, provide the right support, and appreciate it for what it truly is.
Have questions about your Monstera or tips from your own experience with large and small form plants? Share them in the comments below — we’d love to hear from you!
