Do Pothos Help Other Plants Root?

No controlled study has demonstrated that pothos cuttings release enough rooting hormone into water to meaningfully accelerate root growth in neighboring plant cuttings. The idea is widespread in houseplant communities, where gardeners place a rooting pothos alongside a stubborn cutting in the same jar and credit the pothos when roots finally appear. The logic sounds plausible on the surface: plants produce auxin, a hormone central to root development, so a vigorous rooter like pothos might share some of that auxin through the water. But the biochemistry and the available evidence tell a more complicated and less encouraging story.

Where the Idea Comes From

Pothos (Epipremum aureum) roots easily in plain water, sometimes within days, which makes it one of the most forgiving houseplants for water propagation. Gardeners noticed that stubborn cuttings seemed to root more reliably when placed in the same container as a pothos cutting that was already sending out roots. Online forums and social media turned this anecdotal pattern into a widespread tip, often framed as “pothos release auxin into the water, which helps other plants root.”

The kernel of truth here is that auxin, specifically indole-3-acetic acid (IAA), is genuinely critical for adventitious root formation. When a stem cutting is severed from the parent plant, auxin accumulates at the cut base through polar transport within the stem, and this local buildup triggers the cellular program that produces new roots.¹ The question is whether meaningful quantities of that auxin leak out of one plant’s tissues and into the surrounding water in concentrations high enough to influence a second plant’s root formation.

Why Auxin Leaking Into Water Probably Does Not Do Much

Auxin is produced inside living plant cells and transported through specific internal pathways. The hormone moves directionally through the stem toward the base, where it accumulates and triggers root initiation. This process, called polar auxin transport, is tightly regulated by specialized transporter proteins.¹ The plant actively directs auxin to where it is needed. Some auxin does diffuse out of cut tissue into water, but the concentrations are extraordinarily small compared to what commercial rooting products deliver.

IAA also degrades rapidly in water, especially when exposed to light. Placing a jar of cuttings on a bright windowsill, which is what most people do, accelerates this breakdown. Whatever trace auxin a pothos cutting releases into the water has a short half-life and would need to be absorbed by the neighboring cutting’s stem base in sufficient quantity to influence its hormone balance. Research on adventitious rooting shows that this balance is remarkably sensitive: in Arabidopsis seedlings, concentrations of jasmonic acid as low as one billionth of a mole per liter were enough to cut adventitious root numbers in half.² The hormonal environment around root initiation is so finely tuned that even tiny shifts can suppress rooting as easily as promote it. Dumping uncontrolled amounts of random plant exudates into the water is not the precision tool this system requires.

Willow Water Is the Real Comparison

If any plant’s water extract has earned the right to be called a natural rooting aid, it is willow, not pothos. Willow species (Salix) produce genuinely high concentrations of indolebutyric acid (IBA, a more stable relative of IAA) and salicylic acid, both of which promote rooting and help cuttings resist infection at wound sites. White willow shoots collected in mid-March contained IAA at roughly 365 micrograms per milliliter, and salicylic acid peaked at nearly 493 micrograms per milliliter in April.³ These are not trace amounts. They are pharmacologically relevant concentrations, orders of magnitude higher than anything a pothos cutting would release.

Even with those concentrations, willow extracts do not work miracles on every species. In a study on olive cuttings, soaking them in willow bark extract for 48 hours raised the rooting percentage to about 47%, while shoot extract and leaf extract were ineffective for rooting.⁴ A 47% success rate from one of nature’s strongest rooting-compound sources, applied as a concentrated soak, puts in perspective how unlikely it is that trace amounts leaking from a pothos cutting in a shared jar could drive meaningful results in a different species.

The willow comparison matters because it shows what a genuine natural rooting agent looks like: concentrated, deliberately prepared, and applied for extended periods. It is not a passive byproduct of a nearby plant growing in the same jar of water.

Synthetic Rooting Hormone Still Dominates

For gardeners who want the best odds, synthetic auxins like IBA remain far more effective than any natural alternative. A study comparing IBA powder, aloe vera pieces, and other natural substances for rooting softwood cuttings found that IBA treatment produced a rooting success rate of about 67%, with the highest root counts and total root length. Aloe vera, the best-performing natural option in that study, managed around 33% rooting, roughly half the success rate.⁵ Aloe vera’s modest effect likely comes from its gel creating a moist wound seal and delivering a cocktail of growth-promoting compounds, but even that deliberate application underperformed a targeted synthetic hormone by a wide margin.

None of the natural rooting substances studied in the literature operate by passively sitting in a jar next to the cutting. They are applied directly to the cut surface, often as concentrated preparations, to deliver compounds exactly where root initiation begins. The pothos-in-a-jar method skips every step of that process.

The Oxygen Factor You Are Probably Overlooking

If you have tried the pothos trick and felt like it worked, a more likely explanation has nothing to do with auxin. It has to do with dissolved oxygen. Oxygen levels in propagation water have a dramatic effect on root initiation, and anything that gently disturbs the water surface or creates micro-currents can improve aeration enough to make a difference.

Research on weeping fig cuttings found that root initiation happened in 13 days when water was oxygenated to saturation (about 8 milligrams of oxygen per liter), but took 32 days in unstirred water. More strikingly, only half the cuttings in still water rooted at all, compared to 100% in stirred, oxygenated conditions.⁶ That is a massive gap caused entirely by how much oxygen the water contains.

When you add a pothos cutting to a jar, you may be inadvertently improving conditions for the other cutting in ways unrelated to hormones. You change the water more often because there is more plant material in it. You might position the jar differently or use a larger container. A growing pothos root system physically disturbs the water, creating gentle convection that raises dissolved oxygen near the other cutting’s stem base. Any of these factors could explain why a stubborn cutting finally rooted after a pothos was added, without invoking hormone transfer at all.

Pothos May Actually Compete With, Not Help, a Neighbor

An underappreciated wrinkle: pothos are aggressive nutrient scavengers. In hydroponic wastewater treatment experiments, pothos removed an average of about 77% of nitrate from the water and roughly 88% of electrical conductivity (a broad measure of dissolved ions).⁷ In plain terms, pothos strip dissolved minerals from water effectively and quickly.

This is a desirable trait if you are using pothos to clean fish-tank water or treat wastewater. It is less desirable if you are hoping the water in your propagation jar stays nutrient-rich for a second cutting. A cutting trying to develop roots needs some dissolved minerals to fuel cell division, and a pothos hoovering up those minerals may leave less for its neighbor. In a small jar with limited water volume, this competition effect could genuinely slow the other cutting’s progress.

This does not mean pothos poison shared water. It means the net effect of adding a pothos to a propagation jar is not simply “more rooting hormone.” It is a combination of trace hormone release (probably negligible), oxygen dynamics, and nutrient competition. The balance of those factors could easily be neutral or slightly negative for the second cutting, depending on how often you refresh the water and how large the container is.

What Actually Helps Stubborn Cuttings Root in Water

If your goal is to improve rooting success for a difficult cutting, the evidence points toward a few interventions that are far better supported than adding a pothos to the jar.

• Change the water frequently: Fresh water means more dissolved oxygen and fewer bacteria. Stagnant water develops biofilms that can coat the cut surface and block root emergence. Every two to three days is a good rhythm for most cuttings.
• Use a narrow-mouthed vessel: The cutting should sit upright with its stem base submerged but not its leaves. A narrow opening also reduces evaporation and keeps the water level stable.
• Keep it warm but out of direct sun: Bright indirect light supports the leaves’ ability to photosynthesize and feed root development, while direct sun heats the water and accelerates bacterial growth. Warm root-zone temperatures (roughly 20 to 25 degrees Celsius) speed cell division at the cut site.
• Consider a commercial rooting hormone: For genuinely difficult species, a light dip in IBA rooting powder or gel before placing the cutting in water significantly improves the odds.
• Try willow water if you want a natural option: Soak fresh willow twigs (young, green growth, not old bark) in water for 24 to 48 hours, then use that water to propagate your cuttings. The evidence base is at least real, even if the effect is modest compared to synthetic products.

Why the Myth Persists

The pothos propagation trick is a textbook example of confirmation bias in gardening. Pothos are thrown into shared jars with other cuttings that were probably going to root anyway, just slowly. When roots eventually appear on the companion cutting, the pothos gets the credit. Nobody runs the control experiment where the same cutting species sits in an identical jar without pothos, under the same conditions, for the same amount of time. Without that comparison, you cannot distinguish between “the pothos helped” and “the cutting just needed three more weeks.”

There is also a visibility effect. Pothos root so quickly and so visibly that their root mass creates an impression of vigorous biological activity in the jar. It looks productive. The psychological association between seeing lots of roots and expecting more roots is powerful, even when there is no chemical connection between the two plants.

None of this means gardeners who swear by the method are wrong to keep doing it. If the ritual encourages you to check on your propagation jars more often, change the water regularly, and pay attention to your cuttings, those behavioral changes alone can improve your success rate. The pothos is not the active ingredient. Your attention is.

What Pothos Actually Release Into Water

All plants exude a complex cocktail of organic compounds from their roots, including sugars, amino acids, organic acids, and secondary metabolites. These root exudates play roles in nutrient uptake, microbial community management in the root zone, and chemical signaling with soil organisms. Pothos are no exception, and their root exudates in water likely include trace amounts of IAA along with various phenolic compounds.

The problem is that “trace amounts” does not translate to “biologically effective doses for a neighboring plant.” The concentrations of auxin that drive root initiation inside a cutting’s stem base are carefully regulated by the cutting’s own transport and synthesis machinery.¹ External auxin applied at the wrong concentration or in the wrong ratio to other hormones can actually inhibit rooting or promote callus formation (a wound-healing response) instead. The exquisite sensitivity of the rooting process to hormonal balance, where billionth-of-a-mole shifts can halve root numbers, means that uncontrolled hormone exposure from a neighboring plant is as likely to hinder as to help.²

This is why professional horticulturists apply rooting hormones at precise concentrations to specific wound sites rather than broadcasting them into the growing medium. Precision matters. A jar of pothos water is the opposite of precision.

Species That Are Just Hard to Root

Some cuttings resist water propagation regardless of what you add to the jar. Woody-stemmed plants, mature growth from slow-growing species, and cuttings taken at the wrong time of year can be stubbornly reluctant to produce adventitious roots. The difficulty often has nothing to do with what is in the water and everything to do with the cutting’s internal state: its carbohydrate reserves, its age, the thickness of its outer bark layer, and whether the cells near the cut site are competent to respond to auxin signals.

Olive cuttings illustrate this well. Even with concentrated willow bark extract, the best rooting rate in one study was under 50%.⁴ For species like this, the bottleneck is not the availability of rooting hormone in the environment. The bottleneck is the cutting’s own tissue biology. Adding a pothos to the jar will not overcome a fundamental cellular reluctance to form roots.

If you are struggling with a cutting that refuses to root in water, the answer is usually not to add more things to the jar. It is to switch propagation methods entirely: try rooting in a moist perlite or sphagnum moss mix, use a humidity dome, apply a targeted rooting hormone, or take your cutting from younger, softer growth where the cells are more responsive. These approaches address the actual bottleneck rather than adding a lucky charm to the water.