The Monstera deliciosa, often admired for its large, perforated leaves, is a popular houseplant that frequently develops thick, brown, or greenish growths extending from its stem above the soil line. These unusual structures are known as aerial roots, and their appearance can be surprising to new plant owners. The presence of these roots is a completely normal and healthy sign of maturity in your plant, indicating it is fulfilling its natural growth pattern. Rather than a problem, aerial roots are a fascinating structural adaptation that connects your indoor plant to its tropical, wild origins.
Biological Function of Monstera Aerial Roots
In their native Central American rainforest habitat, Monstera plants grow as epiphytes, meaning they naturally anchor themselves onto other structures, such as large trees, rather than rooting solely in the ground. The aerial roots are specialized structures designed to serve a dual purpose in this climbing lifestyle. Their primary function is to provide unwavering structural support, allowing the vine-like plant to ascend the host tree toward brighter canopy light. These roots physically adhere to the rough bark, acting as anchors that stabilize the increasingly large and heavy stem as it climbs.
The second, equally important role of these aerial roots is resource acquisition, which is typical of epiphytic species. Unlike the plant’s soil-based roots that absorb water and nutrients from the potting medium, aerial roots are adapted to pull resources directly from the humid atmosphere. They absorb moisture vapor and trace nutrients from the surrounding air and any decaying organic matter that collects on the surfaces they cling to. This dual system of support and atmospheric hydration is what allows the Monstera to thrive in the dense, competitive environment of the tropical understory.
Proper Management of Aerial Roots Indoors
The appearance of long, unruly aerial roots often prompts home growers to question whether they should be trimmed for aesthetic reasons. While these roots are beneficial to the plant, pruning them is generally safe if done sparingly, as it will not harm a healthy Monstera. If you choose to trim, use sterilized, sharp shears to make a clean cut, being careful not to remove all of the roots at once, which could cause unnecessary stress to the plant. It is often considered a better practice to simply leave the aerial roots alone, allowing them to continue their work of providing additional stability and gathering moisture.
A more beneficial strategy is to embrace the plant’s natural climbing instinct by providing it with a moss pole or a sturdy trellis. This support mimics the tree trunk a Monstera would climb in the jungle, giving the aerial roots a suitable surface to attach to. To encourage attachment, gently direct the aerial roots toward the moss pole and secure the stem of the plant to the support structure. Keeping the moss pole consistently moist is important because the aerial roots will actively root into this humid medium, which in turn provides the plant with extra hydration and stability.
You may also choose to train the roots to grow back down into the pot’s soil, where they will then transition to function like underground roots, further increasing the plant’s capacity for water and nutrient uptake. If the roots appear dry or shriveled, a light misting of the roots themselves or the use of a humidifier near the plant can provide the increased humidity they crave. Avoid submerging the aerial roots in a container of standing water, as they are not designed for full submersion and may be susceptible to rot.
Using Aerial Roots for Propagation
The presence of an aerial root can be a helpful guide when propagating your Monstera plant to create a new specimen. When taking a stem cutting, a successful propagation requires including a node, which is the slightly swollen area on the stem where a leaf and a new stem can emerge. Aerial roots naturally grow from these nodes, making them a clear visual indicator of where to make the cut.
Although an aerial root itself cannot grow into an entirely new plant, its inclusion in the cutting is advantageous. When the cutting is placed in water or a moist medium for rooting, the existing aerial root often gives the new plant a head start in establishing itself. The new soil roots will sprout from the same node where the aerial root originated, and the established root can help the cutting absorb initial moisture more quickly. Air layering is another technique that specifically utilizes the aerial root; it involves wrapping a node and its aerial root in damp moss while still attached to the mother plant, encouraging significant new root development before the cutting is taken.