The arrowhead plant is native to Central and South America, but has gained popularity in the United States because of how easy it is to grow as a houseplant. It is a great choice for novice gardeners looking for an unchallenging first plant to care for.
This plant gets its name from the arrow-like shape of its younger leaves. This initial shape becomes more lobed as the leaf matures. The leaves come in various colors, depending on the species: they can be pink, light green, dark green or white.
One of the most common problems encountered by arrowhead plant owners is when their plants’ leaves turn brown. This is usually as a result of a change in the plant’s environment that is causing the plant stress.
The possible causes of browning arrowhead leaves are insufficient or too much water, too much sunlight, not enough light, low humidity, overfertilization, and incorrect soil.
In this article, we will discuss each of these causes and what you can do to fix them. So, if you are facing a similar issue and wish to learn more, just keep reading!
Why are my arrowhead plant’s leaves turning brown?
Not enough water
The arrowhead plant’s natural habitat is tropical rainforests, where it never runs out of moisture because the environment is so humid. Being adapted to such conditions, it cannot survive long periods without water, and almost immediately presents with symptoms of drought stress if you neglect to water it.
Plants need water not only for moisture, but because it acts as a vessel to transport nutrients from the soil into the roots. If the plant is deprived of these vital nutrients, it will start to weaken and droop. It will prioritize the health of its roots and sacrifice the leaves by cutting them off from the limited remaining resources. This is why the leaves of an underwatered plant turn brown and wilt.
If you do not water the plant in time, it will eventually die.
If you think your arrowhead plant is underwatered, give it a generous soak as soon as possible. Keep pouring water into the soil until you can see excess water flowing out of the drainage holes at the bottom of the pot. This means that all of the roots have had access to water.
Sometimes, the soil in the pot may have dried out so much that it becomes hydrophobic, or water-repellant. In this case, even if you pour water over the soil from above, the water will not be able to penetrate the soil and will instead spill over the edge or down the insides of the pot without reaching the plant’s roots.
If this is the case, bottom watering is the better option. Place the plant in a shallow basin filled with three inches of water, and leave it there for 10 to 15 minutes. The thirsty soil and roots will absorb the water through the pot’s drainage holes until the soil is saturated.
After 10 to 15 minutes, remove the plant from the basin and place it on a drying rack to allow the excess water to drip out for several hours. When there is no more water dripping out, you can return the plant to its usual spot.
Wait for the top two inches of soil to dry out; then repeat the bottom watering technique. Do this for another four watering cycles. The plant should show signs of recovery from drought stress after two to three weeks.
The best way to prevent underwatering is by knowing exactly when your plant actually needs watering. Do this by sticking your finger about two inches into the soil: if it is dry, water the plant, but if the soil is still damp, wait a few days before checking again.
Too much water
Overwatering can arise from giving the plant too much water per watering, watering more often than necessary, using poorly-draining soil or pots, or not adjusting your watering habits to changes in the weather, season and climate.
Overwatering is a common problem in houseplants because many plant owners are a bit too enthusiastic when it comes to watering. They do not always realize how detrimental this practice can be. All of the scenarios mentioned above will result in the soil around the plant’s roots to become waterlogged.
Compromised roots can no longer function properly, and will not be able to absorb the required nutrients for the plant. This means the foliage will discolor and turn brown.
The roots of the arrowhead plant do like moist soil, but they also need to be able to dry out between waterings so that they can have access to oxygen. Constant submersion in water will drown and kill them.
Once dead, the roots will start to rot and become susceptible to opportunistic pathogens like fungi and bacteria. These pathogens will make the rot spread more aggressively through the plant, until all of the roots and the rest of the plant are affected. If you are unable to catch root rot in time, the plant will eventually succumb to the disease.
If you think your arrowhead plant has been overwatered, refrain from watering it immediately and transfer it to a sunnier spot with good airflow. The warmth from the sunlight and the airflow will help to dry the soil out faster.
Do not water the plant again until the top two inches of soil are completely dry to the touch.
If you suspect root rot, you will need to remove the plant from its pot to confirm this. After unpotting it, wash off as much soil from the roots as you can. Do this gently, because the roots will be fragile and you do not want to cause them even more damage.
Inspect all the roots for black or brown sections – these are rotten and will have to be removed. Use a sterile knife or scissors to prune them away until only the healthy, white roots remain.
After pruning it, place the plant on a dry, flat surface to let the roots air-dry for a few hours.
Fill a new pot a third of the way with a well-draining potting mix, place the plant in the middle of the pot and cover the roots with more potting mix.
Do not water the plant yet; wait at least one week before watering it to give the roots time to recover from the trauma of the pruning and repotting process.
Prevent overwatering in the future by developing better watering habits and using pots that have drainage holes at the bottom.
Too much sunlight
The arrowhead plant does not like being left under direct sunlight. It is native to tropical rainforests where it only gets the dappled sunlight that filters through the tree canopy.
If the plant is exposed to too much direct sunlight, its leaves will turn brown and wilt. This is because the higher-than-ideal temperature will speed the plant’s rate of transpiration, leaving the foliage depleted of moisture.
If your plant is getting too much direct light, transfer it to a shadier spot as soon as you can. If you keep it outdoors, place it under a large tree.
If indoors, transfer it to a north- or east-facing window, as these windows will let in bright, gentle sunlight in the morning, but shade in the afternoon when the sun is at its harshest.
If the only windows in your home are letting in harsh light, you can still place the arrowhead plant near them, but place a sheer curtain over the window first to diffuse the light.
You cannot reverse the browning of your plant’s leaves; the damage is permanent.
If the aesthetic of these leaves bothers you, you can prune them off using a sterile pair of scissors. If you do not mind them, then just leave them alone and they will fall off in their own time.
Not enough light
Some people may misunderstand the concept of indirect light and take it to mean that the plant should be kept in low light conditions at all times. This is not true, of course, and insufficient light can also be a reason for the plant’s leaves to turn brown.
If it is kept in a room with too little light, the plant will be unable to perform photosynthesis, which is a plant’s way of harnessing energy from the sun. The pigment, chlorophyll, absorbs light waves from sunlight and stores the energy in cells called chloroplasts until the plant needs to use it.
Thus, without light, the plant has no energy for its continued survival and will no longer be able to produce its own food. No new chlorophyll is produced, causing the plant’s leaves to become paler in color. The more depleted of resources the plant becomes, the weaker and droopier it will be. The older leaves will be the first to lose access to the dwindling resources, which is why they turn brown in color.
A plant deprived of light will also grow leggy as it stretches toward the nearest light source. The leggy stem will be much thinner and longer than normal, and its leaves also smaller than the others. This is the plant’s last-ditch effort to concentrate what little energy it has to grow toward the light, just to keep alive.
If you can see these long stems, your plant has been in poor lighting for a long time and you need to act fast to save it.
If the plant’s leaves are turning brown from insufficient light, find a north- or east-facing window in your home and place it there. If the soil is dry, water it generously. Remove the wilted, brown leaves with sterile if you want to.
Rotate the pot 45 degrees clockwise every four days so that all sides of the plant get some time in the light. This will help the plant grow straight and symmetrically.
Coming from the tropical rainforests, the arrowhead plant is used to a humid environment and will not grow well in a dry climate. The dry air sucks the moisture from its foliage, dehydrating and damaging it.
Low humidity can turn the tips of the arrowhead leaves brown. If this low humidity is constant, the leaves will start to shrivel and droop.
If you live in a drier climate, there are some measures you can take to increase the humidity around your arrowhead plant.
First, you can mist the plant’s leaves with water using a spray bottle. This is helpful, but its effects are very short-lived. Furthermore, the water droplets on the leaves can increase the risk of fungal growth, which is an even bigger problem.
Another good idea is to use a water pebble tray. Place the plant’s pot on top of the pebble tray and, as the water evaporates, it will moisten the leaves as well as the soil in the pot.
If you have other plants that enjoy humidity, place your arrowhead plant near them and let them create a microclimate around each other.
When it comes to the ideal placement in your home, the bathroom and the kitchen are two of the most humid rooms in the house. You can place your plant in either of those rooms, but do make sure that enough light gets into the chosen room.
If you have the means, you can buy a humidifier to easily regulate and maintain the humidity level in the room where the plant is kept. Having a device to keep the humidity between 40 and 60 percent is a blessing for a busy plant owner.
Too much fertilizer
Fertilizing your arrowhead plant can be beneficial if you want it to grow quickly. This is best done in the spring and summer, when the plant is actively growing, and once a month during this period should suffice.
In the colder months, fertilizer is not necessary because the plant is not actively growing, so the nutrients in the soil are more than enough during this time.
If you fertilize your arrowhead plant too much or too often, it can do severe damage to the plant. The excess, unused fertilizer in the soil will turn into mineral salts that will build up around the roots, resulting in soil toxicity and root burn. Root burn causes defective roots and the plant’s ability to absorb water and nutrients will be compromised. Its leaves will present with brown tips and edges and the roots will turn yellow or brown – quite different from their normal white color.
If you think that the browning of your plant’s leaves is due to overfertilization, you need to flush the soil with water to get rid of the buildup of mineral salts. Pour a volume of water into the soil that is equal to five times the volume of the pot. After flushing the soil, wait 30 minutes before repeating the process, and do this a total of four times at 30-minute intervals.
When you are done with the fourth flushing, leave the plant on a drying rack to let the excess water drip out for a few hours before placing it back in its usual spot.
Refrain from fertilizing the plant for a month after flushing while you observe its recovery.
If it does not look like it has improved even after flushing, you might need to repot it and replace the soil with fresh potting mix.
If you fertilize your plant regularly, you can incorporate flushing into your routine as a preventative measure. Flushing the soil once every six months should be enough.
If you use liquid houseplant fertilizer, dilute it to half-strength to be on the safe side.
The arrowhead plant likes soil that retains some moisture. Its roots should be in a moist, but not soggy, environment at all times. When it grows in its natural habitat, the ground is never completely dry and this should be simulated in the conditions you provide in your home.
If you use a potting mix that is too loose and drains too fast, the plant’s roots may not have enough moisture to last until the next time the plant gets watered.
In this case, the plant will present with symptoms of drought stress. It will become more and more dehydrated and soon the leaves will wither, dry up and turn brown.
If you are using the wrong soil for your arrowhead plant, you will need to replace it with a potting mix that contains more organic components. Try not to use soil that has too much coarse sand or perlite, because these components loosen the mix a bit too much.
The aptly-named arrowhead plant gets its name from the arrowhead-shape of its younger leaves. It is a popular houseplant originating from Central and South American tropical rainforests.
This low-maintenance plant has leaves that can be pink, light green, dark green or white, depending on the species. It is a great choice for novice gardeners who do not want a difficult plant to care for.
One of the most common problems encountered by arrowhead plant owners is the browning of their plants’ leaves. The possible causes of this are not enough or too much water, too much sunlight, not enough light, low humidity, overfertilization, and incorrect soil.
Correctly identifying the exact cause of the browning is the first step toward rectifying the problem and returning your plant to full health.
Image: istockphoto.com / Firn