Have you ever looked at your plant and thought, what on earth are those long things growing out the stem? Well, those are aerial roots. “Essentially, aerial roots are root tissue a plant produces up out of the soil,” says Justin Hancock, a horticulturist, from Costa Farms. “A number of different types of plants produce aerial roots, sometimes for different purposes. Aerial roots are more noteworthy now with houseplant parents because many common (and trendy) varieties of houseplants produce them, including many monstera, pothos, and philodendron."
What Is an Aerial Root?
An aerial root is a root that develops on a plant above the surface of soil or water where the rest of the plant's roots are submerged.
"In the right environment, they’re hard to miss," notes Hancock. "On one of my monstera, for example, a couple of the aerial roots are about four feet long.” They can seemingly spring out of nowhere, or you can even use the process of air layering to try and grow them purposefully where you want them (this is great for propagating a rare plant).
Here are five main things to know about aerial roots.
1. Aerial Roots Help Plants Climb
There are so many reasons that aerial roots grow, but one of those reasons is for climbing. “If you think about how a lot of climbing houseplants grow, including English ivy, golden pothos, and Monstera deliciosa, the roots help keep these vines secure as they scale up trees, walls, or other structures — single plants like Rhaphidophora tetrasperma are a perfect example of this,” says Hancock.
If you put a trellis or a moss pole near one of these plants, they’ll often latch onto the surface with their aerial roots so they can grow up in a secure way. This is important to do, especially if you have plants growing up on a wall because they could start to latch onto the wall, causing paint to chip when you eventually need to take the plant down.
2. They Help Strengthen Plants
"Other species, including many ficus, have aerial roots that drop into the soil, strengthen, and help provide support for the trees’ branches. Banyans are a classic example of this,” notes Hancock. On Banyan plants it often looks like the plant has grown legs, these are aerial roots. These plants are very sturdy and often have trunk-like stems. The aerial roots help keep them grounded so they don’t fall over.
3. They Allow For Moisture Absorption
“Epiphytic plants, such as many tillandsia, as well as many orchids, use their aerial roots to absorb moisture from the air, rain, or fog/mist,” explains Hancock. You may also find that if you keep humidity-loving plants in a bathroom, they’ll often sprout long aerial roots so they can seep up all of the extra moisture in the room.
4. Many Kinds of Plants Have Them
“A wide variety of plants produce, or can produce, aerial roots if environmental conditions are right,” says Hancock. “Climbing aroids like monstera, pothos, philodendron, rhaphidophora, scindapsus, etc. are especially popular houseplants that produce them. But you can also commonly find aerial roots on other vines like English Ivy and Climbing Hydrangea.” Plants that grow aerial roots to absorb moisture range from orchids to Staghorn ferns and more.
“You’ll also see aerial roots develop on a number of plants that make baby plantlets—like spider plant, strawberry begonia (Saxifraga stolonifera), and mother of thousands (Kalanchoe daigremontiana),” notes Hancock. “If you have a humid enough environment, you might also see a lot of Ficus species develop aerial roots, including Ficus benjamina and even Ficus lyrata.” Basically you should keep your eyes open around your houseplants. You may start to notice aerial roots in many of your plants.
5. They Shouldn't Be Repotted or Removed
There are a number of things you shouldn’t do to your plants that have aerial roots. One of those things is repotting them just because you’ve seen aerial roots begin to grow. “Because we’re used to seeing roots under the soil, a lot of people have the reaction when they see aerial roots that it must mean a plant is rootbound,” says Hancock. “Repotting to bury aerial roots typically isn’t beneficial to the plant."
Another thing you shouldn’t do is remove the aerial roots of climbing plants. While it won’t directly harm the plant, it makes the plant vulnerable to attacks by pests or diseases because the stem of your plant will now have an open wound.