Anthuriums are one of the houseplants that have gained a massive fan following due to their exotic flowers and leaves.
What if, all of a sudden their leaves and flowers started to turn brown and wilt?
Well, it will look sad right?
Anthurium sunburn is a very common problem that causes leaves and flowers to turn brown and wilt. To revive sunburnt anthurium, the first is to analyze the symptoms, understand the real causes and then revive the plant based on the identified cause.
If you are suspecting that your anthurium is sunburnt, don’t fret. This article has everything related to anthurium sunburn so that you can easily find the problem and revive your plant quickly.
The topic includes,
So, without any further ado, let’s get started.
Causes of Anthurium Sunburn
As the name suggests, sunburn in anthurium is caused by sun damage. But it does not mean that your plant is always getting a lot of light. Even if the light is under recommended range, sometimes factors like high temperature, underwatering and poor potting mixture increase the sensitivity of the plant that triggers sunburn.
Let’s have a detailed look into each of the causes with the scientific reason.
1. Too Much Direct Sunlight
This is by far the most common culprit when it comes to sunburn in anthurium.
It is a known fact that prolonged exposure to sunlight can cause sunburn in any living organism with very few exceptions (Source 1). Unfortunately, anthurium plants do not come under the exception list.
When your anthurium plant gets too much sunlight frequently, the UV-B radiations can cause severe cell damage (Source 2). Furthermore, prolonged exposure to UV-B radiation reduces the chlorophyll pigment and thus directly affecting the photosynthesis process.
Based on a study published in the American Society For Horticultural Science, the lack of enough moisture content in the soil triggers sunburn, especially for indoor plants (Source 3).
This is the reason why many people see sunburn in their anthurium plants even if they are growing under recommended ranges with a grow light.
According to the Oxford Academic’s plant journal, for a dehydrated plant, even the normal light range will be very intense and thus trigger sunburn in the long run (Source 4).
3. High Temperature & Low Humidity
Just like the loss of water, sometimes, the temperature stress alone is enough for triggering sunburn.
Based on a study mentioned in Frontiers In Plant Science, low nighttime temperature followed by high daytime temperature can cause temperature stress in the plant, and as a result, sunburn can occur.
The same study also finds out that low humidity can cause sunburn.
When the water vapor content in the atmosphere is low, the soil gets dry very quickly affecting the plant’s transpiration process leading to dehydration and sunburn.
4. Poor Potting Mixture
If your anthurium is sitting in a poor potting mixture, then it can lead to sunburn in the long run.
A potting mixture can be termed as poor in many ways. But, when we are talking about sunburn, a poor potting mixture is the one that has very low water retention capability.
For example, if your potting mixture has a high amount of normal sand, then it will drain all the water in a short period and artificially create a situation that’s similar to underwatering.
As already mentioned, underwatering is a scientifically proven cause of anthurium sunburn (Source 4).
Signs of Anthurium Sunburn
The most commonly seen symptom of anthurium sunburn is the discoloration of leaves starting from green to yellow and then brown. Once the discoloration happens, then the leaves will start to curl, wilt and dry.
These symptoms are common for many other plant problems, so it is essential that you properly analyze the plant before taking any action.
Let’s have a quick look into each of these symptoms so that you have a better understanding of the condition.
1. Discoloration Of Leaves
Discoloration in the leaves is the common symptom of many anthurium plant problems including sunburn, overwatering, root rot, root bound, etc.
Even though the result of all these problems is yellowing leaves, the underlying cause for the discoloration is different in different scenarios.
As I already pointed out, when too much light falls on your anthurium plant’s leaves, cell damage happens and chlorophyll content starts to decrease. As a result, the leaves start to fade and turn to yellow color.
If no action is taken to fix the root cause, then the discoloration degrades further and yellow spots turn brown and dark brown.
Check out the below image for a closer look at how the discoloration of anthurium leaves looks in real life.
Even though discoloration of leaves is a common sign of many plant problems, yellowing due to sunburn can be easily identified by analyzing the region where the discoloration happens.
If yellow and brown leaves are seen only in the spots where sunlight hits every day, then most probably your anthurium is getting too much lighter than what it wants.
2. Leaves Curling, Drooping, and Wilting
When an anthurium plant gets too much sunlight, the plant will curl its leaves away from the light source to prevent cell damage and loss of chlorophyll.
In some plants, curling is seen first even before discoloration. But the majority of the time, discoloration of leaves and curling happen at the same time.
As I already mentioned, scorching sunlight will dry up the water content in the soil very quickly and it will make the plant dehydrated. Dehydrated plants will look like it’s falling over without the energy to stand straight. This is called drooping and wilting.
Similar to other symptoms, drooping and wilting can also occur due to many other plant problems. But, if your anthurium is wilting during the mid-day when the sun is hottest, then it’s pretty sure that your plant is experiencing sunburn.
3. Flowers drying fast
But, if your plant’s flowers are drying up soon after blooming then probably the light is too harsh for the particular plant.
4. Stunted Or Slow Growth
Just like any other plant problem, if you do not take action to fix the cause causing sunburn in your anthurium, then your plant will go into a slower growth phase.
When a lot of the leaves are dried and dead, the overall photosynthesis process will become slower and the total amount of energy the plant generates will also come down.
As a result of this, the growth of new leaves and flowers will become very slow. Also, the newly grown leaves and flowers will be much smaller than the previously grown counterparts.
At some point, it will reach a situation where there is not enough energy to grow new leaves and it will completely go dormant even in its active growing season.
5. Always Dry Potting Mix
This is pretty easy to understand, right?
Too much direct sunlight or temperature will dry up the water content in the soil mixture very quickly.
If your anthurium soil is completely dry just a day after watering, then the probability of sunburn is very high.
How To Prevent & Revive Sunburnt Anthurium?
After analyzing all the symptoms, if you find that your anthurium is having sunburn, then it’s time to fix the root cause and revive the plant.
Reviving your sunburnt anthurium depends on the cause. Here are the step-by-step instructions to revive without stressing your anthurium plant too much.
1. Move the plant away from light
Irrespective of the cause, the first step in reviving your anthurium from sunburn is to move the plant away from the light source you are currently using.
If the primary cause for your anthurium sunburn is anything other than too much light, then this is a temporary adjustment. Keep the plant in a low-light environment for a couple of days to cool off the leaves while you fix the root cause.
Once the plant settles in, move it back to its original location and monitor the growth.
On the other hand, if your anthurium is sunburnt due to too much light hitting the plant, then this is the only thing you have to do. Simply move your plant away from the light source.
If moving is not an option, then try to reduce the intensity of light by using a radiation filter or semi-transparent cloth curtain.
For anthurium plants grown under grow light, keep the intensity anywhere inside the range of 1500 to 2000 foot candles for optimum growth (Source 5).
2. Keep an eye on the temperature
If the sunburn is due to high temperature, then after moving your plant to a low light environment, monitor the temperature of the soil using a stick thermometer.
Anthuriums prefer temperatures between 70 and 86 oF (22 and 30 oC). If the temperature is above 30 degrees, then try to place the plant in a room with an air conditioner or air cooler.
Once in a while, you can water your plant with cool water (20 to 25 oC).
But, never use cold or chilled water for your plants, because it will trigger root shock that can lead to permanent root damage.
3. Use slightly moist soil
If you live in a hot country, then overwatering slightly may be a good choice to keep your anthurium plant hydrated throughout the day.
Either you can increase the composition of the water-retaining ingredient in your soil (peat moss/coco coir) or decrease the water draining ingredients (perlite/clay pebbles) to increase the overall moisture retention in the potting mix.
But always ensure that you are not going overboard while overwatering, because overwatering can lead to root rot in the long run which can be fatal to your plant if untreated.
Some plant owners suggest misting your plant during the mid-day instead of overwatering. There are no scientific studies to prove this claim, but you can try them out if you want.
Anthurium Sunburn – Frequently Asked Questions (FAQs)
In this section, I will answer some of the commonly asked questions asked on different forums related to anthurium sunburn.
Should I cut sunburnt brown leaves off my anthurium plant?
Yes, it is safe to cut back the sunburnt brown leaves from your anthurium plants. It is advised to use sterilized equipment so that no bacteria or fungal infection happens.
How much sun can an anthurium tolerate?
Anthurium plants are grown well in a moderately lit environment with direct morning or evening sun. To be precise, a light source in the range of 1500 to 2000 foot candles for 10 hours a day is ideal.
Even though they can tolerate a couple of hours of direct sunlight every day, it is not recommended due to the high chances of sunburn.
Is my anthurium getting too much sunlight?
If you are seeing a lot of yellow or brown leaves in the side where the light falls on your anthurium, then there is a high chance that your plant is getting too much sunlight. Other signs include always dry soil, curling, and wilting leaves, slow growth, etc.
When it comes to growing conditions, anthuriums are not too picky and they are even considered to be very adaptable.
But, there is a limit to everything. You cannot expose a plant that loves indirect light to full sunlight for 6 to 7 hours a day and complain about sunburn!
So, instead of blaming the sunlight and your anthurium plant, be proactive and provide filtered sunlight to your plant and witness the beautiful blooms throughout the year.
To back up the information we provide in our articles, the Plantials team only uses high-quality sources published in peer-reviewed university or scientific research journals.
- Effects of UV-B radiation on photosynthesis and growth of terrestrial plants, National Center For Biotechnology Information.
- Some Effects of Ultraviolet-B (UV-B) Radiation on the Biosphere, NASA Earth Observatory Journal.
- Water Stress Increases Sunburn, American Society For Horticultural Science.
- Entire Photodamaged Chloroplasts Are Transported to the Central Vacuole by Autophagy, The Plant Cell, Oxford Academic.
- Anthurium Flowering Plant, TNAU Agritech Horticulture.