What Is an Aerial Root and What Should You Do With It?

An aerial root is any root that emerges from a plant’s stem or branches above the soil line rather than underground. Far from being a sign that something is wrong with your plant, aerial roots are a normal adaptation that helps certain species cling to surfaces, absorb moisture from the air, and even photosynthesize. They show up on many popular houseplants, and understanding what they do will help you decide whether to leave them alone, tuck them into soil, or trim them back.

How Aerial Roots Differ from Underground Roots

Underground roots grow in a dark, moist, nutrient-rich environment and are built accordingly: fine root hairs spread through soil particles to pull in water and dissolved minerals. Aerial roots face a completely different set of problems. They hang in open air where humidity can swing from saturating to bone-dry in a few hours, they have no soil to anchor into, and they often need to attach themselves to bark, rock, or a moss pole. As a result, they develop specialized tissues that underground roots simply do not need.

In orchids, the most obvious adaptation is a spongy outer layer called the velamen. This whitish-silver sheath can soak up water within seconds, while evaporation from the same tissue takes several hours, giving the root a sustained window to absorb what it captured from a brief rain or a burst of mist.¹ Studies on epiphytic orchids growing in different microhabitats show that aerial roots also develop thicker cell layers, reinforced inner walls, and other drought-adaptive traits that soil-bound roots of the same species lack.² In climbing aroids like Monstera or Philodendron, the roots instead grow a tough outer surface and fine hairs that release a sticky mucilage to glue the plant to its support.

The Jobs Aerial Roots Actually Do

It is tempting to think of aerial roots as roots that just happen to be in the wrong place, but they serve several distinct functions depending on the species. Most plants that produce them rely on aerial roots for more than one purpose at the same time.

• Anchoring and climbing: Root-climbers like English ivy and Syngonium use clusters of aerial roots to grip bark, walls, and other surfaces. In Syngonium, the attachment is a multi-step process where root hairs release a glue-like substance and then undergo an unusual shape change, curling into helical structures that dissipate energy under wind and load, preventing the root from ripping free.³
• Water and nutrient uptake: Epiphytic orchids, which grow on tree branches with no soil contact at all, depend on their aerial roots to capture rainwater and dissolved nutrients from bark runoff. The velamen’s rapid absorption is critical for survival in a canopy environment where water availability is brief and unpredictable.
• Structural support: Many tropical trees, including mangroves and large rainforest species, send aerial roots downward from their trunks or branches to brace themselves in unstable substrates. In Amazonian forests, stilt roots and buttresses are more common in valley soils and among tall, slender trees whose proportions would otherwise make them top-heavy.⁴
• Gas exchange: Mangrove pneumatophores, the finger-like projections that poke above mudflats, allow roots buried in oxygen-depleted sediment to breathe. Photosynthetically generated oxygen in these structures can diffuse downward into submerged roots, which helps species like Sonneratia alba and Avicennia marina thrive in zones where tidal flooding is frequent.⁵

Climbing aroids actually produce two distinct categories of aerial roots at each node. Clasping roots are short, numerous, and press flat against the support to hold the stem in place. Feeder roots are longer and thicker, often dangling downward toward the ground. As the plant climbs higher, both types increase in number and size, but the feeder roots are the ones maintaining a hydraulic lifeline to soil-level moisture and nutrients.⁶ That distinction matters when you are deciding what to do with the roots on your pothos or Monstera at home.

The Surprising Photosynthesis Angle

Green aerial roots are not just green for show. Orchid aerial roots contain chlorophyll and can carry out photosynthesis using two different biochemical pathways: the standard one during the day and a water-conserving mode at night. The daytime rate of carbon fixation is much higher, but measurements of overall gas exchange show these roots still release about as much carbon dioxide as they fix, so they are not truly self-feeding the way a leaf is.⁷ So what is the point? Research on Phalaenopsis, the moth orchid commonly sold in grocery stores, suggests the bigger benefit is oxygen production. When a thick, fleshy root is tightly wrapped in damp velamen, the interior can become oxygen-starved. Photosynthesis inside the root generates enough oxygen to prevent that internal suffocation.⁸ This means that the green tips of your orchid’s aerial roots are genuinely performing a physiological function, and keeping them exposed to some light is worthwhile.

Common Houseplants and Their Aerial Roots

If you grow tropical houseplants, you have almost certainly seen aerial roots. Monsteras produce thick, rope-like ones that can reach the floor. Pothos (Epipremnum aureum) sends out thinner, wiry roots at every node. Philodendrons do the same. Hoyas push out short, stubby aerial roots along their trailing vines. Orchids grow silvery-white roots that wander out of the pot and into the air. Each of these species evolved as an epiphyte or semi-epiphyte in humid tropical forests, so aerial root production is part of their basic growth program, not a distress signal.

A common worry is that a burst of aerial roots means the plant is rootbound, underwatered, or otherwise unhappy. That can sometimes be a contributing factor, especially if the underground root system is severely compromised, but in most cases the plant is simply doing what it would do in nature. In the wild, a Monstera starts life on the forest floor and then climbs a tree trunk, eventually losing contact with the ground entirely. Its aerial feeding roots take over the job of water and nutrient delivery, and the base of the stem can even die back without killing the plant.⁹ Your living room Monstera is running the same genetic script even though it has nowhere to climb.

What to Do With Them on Indoor Plants

You have three basic options, and none of them is categorically wrong. The best choice depends on your plant, your setup, and how much you care about aesthetics versus growth.

Leave them alone. This is the lowest-effort and often the best option. Aerial roots do not harm the plant by existing, and they actively contribute to its health. A study comparing three popular aroid houseplants grown under typical indoor humidity found that aerial roots showed the greatest increase in biomass when humidity was raised, suggesting these roots are actively absorbing moisture and nutrients from the surrounding air.¹⁰ Even at normal household humidity, aerial roots contribute to the plant’s overall uptake capacity. Misting them occasionally or running a humidifier nearby gives them more to work with.

Direct them into soil or onto a support. If your Monstera or Philodendron is on a moss pole or trellis, you can gently guide aerial roots toward the pole and pin them against it with plant ties. They will attach on their own over time, and the plant will climb more vigorously because it is getting the mechanical and nutritional support it evolved to seek. Feeder roots that are long enough to reach the pot can be tucked into the soil, where they will function like any other root. For orchids, you can redirect a root that has escaped the pot back into the potting medium, but do it while the root tip is still actively growing (the green or reddish tip). Once the root has hardened and silvered over, bending it risks snapping it.

Trim them. If the look bothers you, you can cut aerial roots off with clean scissors or pruners. The plant will not die. But you are removing a functional organ, and the plant may simply grow replacements. For orchids especially, aggressive trimming of healthy aerial roots reduces the plant’s moisture-absorbing capacity. A reasonable compromise is to trim roots that are brown, shriveled, or clearly dead while leaving green or silver healthy ones intact.

Humidity and Aerial Root Health

The single biggest environmental factor for aerial root performance indoors is humidity. In a tropical forest canopy, relative humidity often hovers above 70 or 80 percent. The average home sits somewhere between 30 and 50 percent, and in winter with central heating running, it can drop below 30. Under those conditions, aerial roots dry out quickly, turning brown and papery. The plant is not dying, but those roots are no longer doing much useful work.

The research on Anthurium, Epipremnum, and Philodendron grown at high versus ambient humidity showed that all three species grew more overall when humidity was elevated, with aerial roots showing the largest biomass response.¹⁰ If you want to encourage healthy aerial root growth on your aroids, a humidifier in the same room makes the biggest difference. Grouping plants together, placing pots on pebble trays with water, or growing in a bathroom with a shower all help too. For orchids, the velamen’s ability to absorb water within seconds and release it slowly over hours means that even a brief daily misting can be effective.¹

Propagation and Aerial Roots

Aerial roots are your best friend when propagating climbing aroids. A stem cutting taken just below a node with an aerial root already emerging will root faster in water or sphagnum moss than a cutting without one. The aerial root is pre-formed root tissue, and once submerged in water or pressed into a moist medium, it readily transitions to functioning as a soil root. This is why propagation guides for Monstera and Philodendron always tell you to include at least one node with an aerial root in your cutting. Without one, the cutting has to generate root tissue from scratch, which takes longer and has a higher failure rate.

For orchids, the situation is different. You cannot propagate a standard Phalaenopsis by cutting off an aerial root. Orchid aerial roots lack the meristematic tissue needed to regenerate a new plant. Keikis, the baby plantlets that sometimes sprout from orchid flower spikes, do come with their own aerial roots, and those roots are what allow you to pot the keiki independently once the roots are a couple of inches long.

Microbial Communities on Aerial Roots

Aerial roots are not sterile surfaces. They host complex communities of bacteria and fungi that shift as the root matures. Research on the aerial roots of Cissus verticillata, a tropical vine, found that each stage of aerial root development, from young and free-hanging to mature and touching a surface to those that have reached the ground, supported a distinctly different microbial community. Bacterial functions stayed relatively stable across all three root stages, but fungal communities shifted considerably.¹¹ This microbial variability likely influences how well the root acquires nutrients and resists pathogens in different environments.

For indoor growers, the practical takeaway is that aerial roots benefit from exposure to a living environment rather than a sterile one. Wrapping them in damp sphagnum moss or pressing them against a bark support does more than just provide moisture; it gives the root a surface where beneficial microbes can establish. This is one reason why moss poles often outperform bare stakes for supporting climbing aroids. The moss creates a microhabitat that aerial roots are adapted to colonize.

Living Root Bridges and Engineering Inspiration

Some of the most striking applications of aerial roots exist far from anyone’s windowsill. In the subtropical forests of Meghalaya, India, the Khasi and Jaintia peoples have been building bridges from the living aerial roots of Ficus elastica (rubber fig) for centuries. A cutting is planted on one bank, and once it matures, its aerial roots are guided across a bamboo framework spanning the river. Over years, the roots anastomose, fusing together into a mechanically stable lattice that strengthens with age rather than degrading like a conventional bridge.¹² Some of these bridges are over 50 meters long and continue to bear foot traffic after more than a century.

The attachment mechanics of climbing aerial roots have also caught the attention of engineers studying bioinspired adhesion. The way English ivy’s clustered roots grip bark, and the way Syngonium’s helical-crack root hairs dissipate energy under mechanical stress, offer models for adhesive systems that could work on rough, irregular surfaces where conventional glues fail.^{13 3} The research is still in its early stages, but the underlying principle is compelling: millions of years of evolution have already solved attachment problems that roboticists are just beginning to tackle.

When Aerial Roots Signal a Problem

While aerial roots are overwhelmingly normal, there are a few situations where a sudden explosion of them can tell you something useful about your plant’s condition. If a climbing aroid that has been stable for months suddenly pushes out aerial roots at every node, it may be searching for something: more moisture, a support to climb, or light. Climbing aroids in nature grow toward darkness initially (a trait called skototropism, because darkness signals the presence of a tree trunk), and the aerial roots help the plant grab hold once it finds one. A plant in a bright room with nothing to climb can keep producing roots in a kind of ongoing search.

Orchid aerial roots that are uniformly shriveled and dry, with no green or silver plump sections, indicate that ambient humidity is too low or the plant is severely dehydrated. Roots that are mushy and brown, on the other hand, suggest overwatering or rot, though this is more common in potted roots than aerial ones. The velamen of a healthy aerial root should feel firm and papery when dry, and become green and slightly translucent when wet. If you see that cycle happening, the root is working properly.

For any houseplant, aerial roots growing exclusively upward rather than downward or outward can indicate that the air above the plant is more humid than the air below, which sometimes happens near ceiling vents or in terrariums. The roots are simply growing toward the moisture gradient. Adjusting airflow or humidifier placement can redirect this growth if it is not what you want.

The Evolutionary Puzzle

Roots themselves are not a single invention. Research on fossil plants and their living descendants suggests that roots evolved independently at least twice in the history of land plants, once in the lineage that includes clubmosses and once in the lineage that includes ferns and seed plants. The extensive similarities between these two root systems, including features like root caps, represent convergent evolution rather than shared ancestry.¹⁴ Aerial roots, in turn, evolved multiple times within these lineages, appearing independently in orchids, aroids, figs, mangroves, ivy, and many other groups. Each time, the selective pressure was similar: a plant needed to solve the problem of anchoring, absorbing water, or exchanging gases in a habitat where underground roots alone were not enough. The fact that so many unrelated lineages arrived at the same general solution speaks to how powerful a strategy it is.