There are some thick brown aerial roots that have emerged from the nodes on the stems of your pothos. So, you’re probably asking yourself: “are aerial roots a sign that something is off with my pothos”? “Do they serve any useful function”? Read on to know why aerial roots are growing on your pothos.
Aerial roots are likely to grow on your pothos if you let the stems spill over the wall, container, or other plants. It’s trying to cling to them for support. It may grow due to lack of light, nutrient deficiencies, and watering problems.
What Are Aerial Roots?
As the name suggests, aerial roots grow in the air rather than in the soil. They usually develop on the plant parts located above the ground, such as the stems, shoots, etc. They can also be referred to as air roots.
Aerial roots on tough vining plants like pothos serve as anchors. That means they help the vines affix to structures like walls, rocks, trellises, and other plants for support.
In most cases, they also double up as ‘breathing roots,’ meaning they help extract and absorb nutrients, gases, and moisture from the air in the surrounding environment.
Air roots are most common on epiphytes, which are plants that grow on other plants. They include plant species like pothos, epiphytic orchids, rubber trees, philodendrons, and monstera – just to name a few.
What Are The Functions of Aerial Roots?
Aerial roots serve many different purposes that often vary from plant to plant. However, their core function generally revolves around adaptive survival and support.
Aerial Roots Help Stabilize Plants
Like normal roots that grow in soil, aerial roots are intended to improve the stability of their parent plants. It’s especially true for epiphytes and vining plants that need to attach to supporting structures for stability and growth.
Specifically, these air roots help a plant affix itself to rocks, trellis, other plants, walls, and various other structures. In this way, aerial roots act as anchors, helping vining plants like pothos climb host trees and walls. The benefits of doing so are numerous – for instance, the vining plant can catch more light at an elevated position.
Plants like rubber trees grow aerial roots to add supportive strength to soil roots. After all, these trees can be gigantic and need all the root support they can get.
Aerials Roots Helps Nourish the Plant
Again, aerial roots perform almost the same function as underground roots. In this case, they help the plant draw nutrients. They usually absorb nutrients dissolved in rainwater, dew, or mist that fall on the roots or run down the host tree/structure.
This function is more prominent in plants like epiphytic orchids. They hang their aerial roots in the air, allowing them to get extra nutrients from water dripping off leaves above the plant.
Aerials Roots Helps Absorb Moisture
Aerial roots help plants like monstera, pothos, and orchids take up moisture (along with dissolved minerals and nutrients).
They can absorb water directly from the air around them. Or, more commonly, from rainwater, water that’s trickling over host trees, and water dripping off foliage above the plant.
Aerial Roots Help Plants ‘Breathe’
Aerial roots can play a crucial role in helping some plants adapt to living in bogs, marshes, coastal swamps, ravines, and other wetlands. Their underground roots are pegged into marshy water or soil that has low to no oxygen.
Because they cannot absorb oxygen from their terrestrial roots, they need aerial roots to do the job. Otherwise put, they perform the function of air exchange. Aerial roots on pothos are well-equipped to do this, especially when potted in a poorly-drained mix.
Aerial Roots Can Help with Propagation
In addition to providing anchoring support, absorbing nutrients, and breathing, aerial roots can be pretty valuable when it comes to propagation. It’s an important function that they provide in plants like pothos.
You see, taking cuttings with aerial roots boosts their survival dramatically. That’s because aerial roots are highly likely to maintain their growth when in the soil or water. As such, these air roots make propagating more feasible, easier, and quicker.
They help the plant absorb the much-needed nutrients, moisture, and minerals it needs to grow new roots, stems, offsets, and leaves.
Identifying and Evaluating Causative Factors
Pothos is a hardy vining plant that grows as an epiphyte in its native habitats in South Pacific areas like the Solomon Islands.
In other words, pothos naturally put out air roots from stem nodes primarily for climbing and anchoring on other plants for structural support. They also help with the absorption of nutrients and moisture.
Aerial roots on pothos usually appear as thick, fleshy nubs. You’ll typically find a single air root sticking out from nodes and internodes along the vining stems. Although harmless, aerial roots may look unsightly to you.
It’s important to note that there is a lot of debate on what leads to the growth of aerial roots on pothos. Interestingly enough, they may appear on some of your pothos plants and not in others.
That being said, here are some key causative factors to keep in mind:
Although native to highly humid rainforest environments, pothos is quite tolerant of most levels of humidity. It turns out, very high humidity seems to favor the growth of aerial roots on the long stems of pothos.
Pothos seem to produce more aerial roots in order to take advantage of the humid conditions. They’re trying to get as much moisture out of the atmosphere as possible. So, if you keep your pothos in a bathroom, greenhouse, or terrarium, which is probably why it’s growing aerial roots.
In addition to high humidity, low light is another factor that facilitates the growth of aerial roots on pothos. This may be an adaptive response in a bid to climb higher where it’ll possibly get more light.
Of course, other symptoms of light shortage include leggy, floppy, or stretchy growth. In fact, most aerial roots on pothos emerge on stems with longer internodes. The leaves may also appear stunted, turn yellow, or start losing their variegations.
Slowed or distorted growth is another telling sign that your pothos isn’t getting enough light. It would be best to shift your pothos to a brightly lit area where it will enjoy filtered or indirect natural light. In due time, it’ll thrive and regain its variegation.
Too High Temperatures
Pothos does best in ideal temperatures in the range of 70-90°F (21-32°C). Temperatures below 70°F (21°C) will likely cold-stress your plant. Your pothos will show displeasure to temperatures that dip below 55°F (12°C) by wilting, withering, and shedding leaves.
On the other hand, exposure to high temperatures exceeding 90°F (32°C) will stunt the growth of your plant. More than that, stress arising from high temperatures and heat tends to stimulate pothos to produce new roots, both terrestrial and aerial.
This is often seen when your pothos is subject to a hot & wet environment. The high heat seems to be quite favorable for aerial root growth. (Source: University of Florida)
Water Supply Problems
Too much or too little water is top of the list of issues that may affect your pothos. Overwatering is especially harmful, suffocating the roots and causing root rot. When roots are damaged, your pothos will likely respond by generating more aerial roots to compensate for root loss below the soil surface.
The longer your pothos sits on wet soil, the more damage it will cause. As well as sprouting more air roots, overwatered pothos will show signs of leaf yellowing, browning, and drooping. The leaves may become soft, blackened, and eventually fall off.
Too little water, on the other hand, will moisture-stress your plant and cause stunted growth. Besides, underwatering makes it hard for roots to take up water, minerals, and nutrients, thus diminishing your plant’s health. It may also cause or worsen the effects of fertilizer salt build-up.
All of these adverse consequences of underwatering don’t just stress your pothos. They may also stimulate your plant to develop aerial roots to get more nourishment and moisture from above the ground.
Nutrients are In Short Supply
Not all problems inflicting a pothos plant are caused by watering, temperature, and light problems. Sometimes, your pothos may grow aerial roots and show signs of unhealthy growth due to a lack of nutrients.
Nitrogen deficiency, for instance, manifests as leaf yellowing, loss of variegation, and distortion of stems & foliage. Talking of distortion, the emergence of more aerial roots maybe a reactionary growth. Your pothos is trying to find ways to get more nutrients.
Extreme lack of molybdenum, calcium, zinc, and manganese also cause stems to become floppy, distorted, and leggy. The aerial roots will likely show up in addition to narrow leaves and interveinal yellowing of new growth.
If you’re too keen, you’ll notice that aerial roots typically emerge from areas of injury or damage. This could be due to cold injury, physical injury, or other traumatic incidents. These aerial roots are, in themselves, not harmful to your pothos.
However, aerial roots may be a symptom of stress or that your pothos has experienced damage or some injury in recent days or weeks. Maybe the roots have been damaged by too much fertilizer. Or perhaps you accidentally bruised the stems.
How Do You Get Rid Of Aerial Roots On Pothos?
As I’ve mentioned many times, aerials roots are rarely harmful to your plant. However, they can be unsightly and impact the ornamental value of your houseplant. Thankfully, there are ways you can deal with them.
Push Them into the Soil
Bury the nodes that contain the roots. This is the easiest and perhaps the most helpful way to get rid of aerial roots (if they’re not looking too good above the soil).
Not only will these roots continue to grow, but they’ll also serve the function of normal roots – i.e., they will start absorbing nutrients and moisture from the soil.
Trim Off the Aerial Roots
If you find aerial roots unsightly on your pothos, that’s good and awesome. Take a sterilized pair of scissors, pruning shears, or sharp knife and trim them away. This action won’t harm your pothos; it may actually promote healthier, lusher growth of foliage.
Make sure to cut the aerial roots as close to the stem as possible. Don’t be surprised if the aerial roots shoot back after cutting, though.
So, it would be best to remedy the situation that’s causing them to grow in the first place – such as providing bright, indirect light, avoiding exposure to heat/high temperatures, and watering your pothos properly.
You don’t have to throw away the aerial roots you cut from your pothos. They can serve a beneficial purpose in propagation.
- Make a few stem cuttings, ensuring each has at least a node, aerial roots, and 3-4 top leaves.
- Sterilize the cutting tool with every snip of the stems to prevent the transfer of pathogens.
- Pothos can be toxic (has a substance called calcium oxalate), so make sure to handle using a pair of gloves. Also, please wash your hands thoroughly after handling them.
- Root the stem cuttings in soil (you can use vermiculite instead) or water. The soil should be evenly moist; keep them out of direct sunlight. It will take about 3-4 weeks for propagated pothos cuttings to produce enough roots in water.
- Once new roots have emerged, plant your new pothos in a fresh, sterilized batch of potting soil.
Can You Propagate Pothos From Aerial Roots?
No, you can’t propagate pothos from aerial roots only. It would help if you rooted a stem cutting with a node, leaves, and an aerial root in water or soil. Aerial roots, in themselves, don’t possess the genetic and specialized cells needed to regenerate a new plant.
Why Are Pothos Aerial Roots Drying Out?
Aerial roots on your pothos may dry out due to extreme lack of humidity, overexposure to direct sunlight, hot drafts, cold injury, and underwatering. You can correct this by misting the roots, using a humidifier, or setting your plant on a shallow water tray with pebbles.