Chlorophyll is responsible for the vibrant green color of most plant leaves. If they begin to turn yellow, brown, or black, it indicates something is wrong.
Given that Schefflera plants can thrive in almost any indoor growing environment, the fact that their leaves are turning black is a clear indication that there is a problem with the plant’s health.
Black leaves on Schefflera indicate frost or cold damage. Additionally, various foliage diseases, such as bacterial leaf blight and Alternaria leaf spots, can cause blackened leaves. Schefflera leaves turning black is caused by environmental factors such as low humidity, lack of light, and heat stress.
Continue reading to learn why Schefflera leaves turn black and how to remedy the situation.
Causes of Leaves Turning Black
Being a tropical plant, Schefflera loves high humidity and warm temperatures.
If your Schefflera is in an area that has low humidity, you may notice that the leaves will begin to turn black and drop off.
Because of low humidity, the leaf cells tend to lose more water than usual. It can cause damage to the cell structure, and some of the die eventually, which you will as leaves turn black.
Place your schefflera on a tray of pebbles with water to increase humidity. Spraying the leaves also works, though do not soak the leaves – a gentle misting is sufficient.
Also, investing in a humidifier can solve this problem for your other houseplants as well.
This is the worst situation for any plant which loves to thrive in well-lit conditions.
Schefflera are tropical plants that grow well in lots of light, so leaves that don’t receive enough light can turn black and fall off.
Like other plants, Schefflera also needs light to produce food and chlorophyll.
If you do not ensure the light requirement the leaves will eventually turn yellow, brown, and ultimately black.
Place your Schefflera in an area that has loads of sunlight. The south-north-facing window is the best location for your houseplants to thrive including Schefflera.
You can consider setting up artificial light if your apartment doesn’t have enough natural light access.
Schefflera loves medium to bright light and can grow well in full sunlight. Studies have shown that Schefflera plants can tolerate temperatures between 45- 105°F (16°C – 40°C) without suffering from cold or heat damage.
If your Schefflera is exposed to extreme heat conditions then the delicate leaf cell will start to get damaged. Death leaf cells will not show vigorous green color.
Unfortunately sunburnt or heat-damaged leaves won’t recover, so it’s best to prune them away.
Place your plant in an area that has enough light but not severe heat that can cause heat shock.
Leaves subjected to extreme cold will appear wilted and water-soaked. Extreme cold for Schefflera is temperatures below 50°F (10°C).
Because below this temperature level, the Schefflera stops the photosynthesis process.
These leaves will turn brown or black and eventually turn crispy and die.
Do not immediately prune away the damaged foliage, as it helps insulate the plant from further damage.
Move the Schefflera into a warmer area and make sure the temperature is at least 50°F (10°C).
Houseplants detest drafts – plain and simple. They’re called ‘house plants’ because they thrive indoors, and cold or hot drafts will damage them. Hot blasts of air will burn leaves. Drafts can also cause the Schefflera leaves to curl.
Ensure to keep your Schefflera away from open windows, fireplaces, air conditioners, heat vents, radiators, appliances, etc.
Move your Schefflera to an area protected from drafts, or set up a barrier to prevent drafts from radiators hitting your plant.
I talk about this one often, but it really is a severe disease that can have fatal consequences if left unchecked.
Root rot occurs due to overwatering, poor drainage, and water-logged soil that can’t take oxygen in.
This fungal disease attacks the root system, turning them into a black, soggy, mushy mess.
Root rot damages the normal functionality of the root system. It can no longer intake the essential elements or water.
Consequently, the Schefflera leaves start to turn yellow, brown, and black.
Prevent root rot by being careful to not overwater your plant. Also, let it dry out between waterings.
Your Schefflera needs both oxygen and water to thrive. That’s why it is important to dry out between waterings.
If root rot develops, you need to remove all the diseased roots with a sterile pair of scissors or pruning shears and replant the Schefflera into a clean container.
You can use this technique if there are some healthy roots remaining.
Black Spots on Leaves
Alternaria Leaf Spot
Alternaria leaf spot mainly occurs in leaves but sometimes you may see this on stems also. This is a fungal disease caused by the Alternaria genus.
This is very easy to identify if you know how to look for it. Now, if you find concentric brown spots appearing on the underside of the leaves, it’s just the beginning.
A few days later the same spots will appear on the upper side of the leaves also.
Eventually, the spots increase in diameter and turn black and gray conidia of fungi become visible.
High humidity above 90% and temperature above 82-84°F (28-30°С) is favorable for Alternaria to occur.
You need to treat this kind of fungal infection with an effective fungicide like Liquid Copper Fungicide.
Make sure to place your Schefflera in a well-ventilated area. Also, make sure the plant is away from any kind of heating appliances.
Do not keep the plant close to other plants because fungal spores spread through the air quickly.
Also, cut off excess leaves to make sure the plant gets enough light and fresh air.
Bacterial Leaf Blight (Caused by Pseudomonas cichorii)
Initially appear as small, water-soaked areas that rapidly enlarge and eventually turn black.
Severe leaf drop is also common in plants affected by blight. Appearance is similar to plants infected with Alternaria leaf spot disease.
When you find out the first sign of this disease, cut off the leaves and branches. Treat the cut site with a 1% solution of copper sulfate (100 g per 10 L of water).
Or a 0.7% solution of ferrous sulfate (70 g per 10 water). Your best bet is to maintain the dry foliage and remove all infected leaves.
Schefflera, attract a wide variety of pesky insects. Aphids, Caterpillars, Fungus Gnats, Mealybugs, Mites, Scales, Shore Flies, and Thrips are among the pests drawn to the Schefflera.
Pear-shaped insects vary from light green to brown. You are more likely to notice a sooty mold or honeydew before noticing the aphid infestation.
The mold, which develops in the secretion of aphids, can cause leaves to have a black appearance.
Small, flat tan to brown insects that attach themselves to plants and feed on plant flesh. The soft scale variety secretes honeydew, which sooty mold thrives in.
Tiny, black flies that fly around or run across the surface of the soil. The larvae of these insects feed on the roots, root hairs, leaves, and lower stems.
As a result, plants may become more susceptible to diseases that can turn leaves them black.
White, cottony clumps appear on plant leaves and stems. They appear on the lower leaves and roots of plants found in warm, moist habitats.
They wreak havoc by feeding on plant juices. As with aphids, honeydew and sooty mold will appear.
Mealybugs are also vectors of various plant diseases and severe infestations can cause parts of the plant to die.
Mites (Broad Mite)
Are so small that they will go unnoticed until there is severe damage to the plant. Broad mites cause necrosis of foliage of the vegetative shoot apex.
Mites (Two-spotted Spider Mite)
Like its broad mite cousin, these mites are extremely tiny and aren’t noticed initially. Damaged foliage can turn yellow or develop speckles.
It’s easy to mistake webbing produced by this mite for dust underneath leaves, so be sure to regularly wipe them down. Miticides are effective at controlling these pests.
Pesticides and neem oil are effective at getting rid of pests. Neem oil is the better option because it is an organic repellant.
You can directly spay it onto mealybugs, aphids, and mites to instantly kill them.
Salt in the Soil
The soil you use to grow your Schefflera in will determine the quality of the plant. If there is too much salt in the soil, you are going to have problems.
Tap water, fertilizers, and potting mixes all contain salts, so you need to be careful when watering and fertilizing your Schefflera.
Look at the surface of the soil. Are there any white spots? This could indicate a salt buildup.
Check fertilizer rates to make sure there are no excessive amounts of salt.
Water sources should be below 1000 ppm soluble salts.
Leach pots with 2-4 inches of water to reduce the salt levels.
Always apply SRFs (slow-release fertilizers) evenly on the soil surface.
Schefflera is the kind of plant that needs a significant amount of light, due to the dense foliage. If it’s in an environment that has dismal weather, be it indoors or outdoors, it will not thrive.
When I talk about dismal, I mean constant rainfall or cloud cover preventing sunlight from reaching the plant.
Use artificial light to ensure the Schefflera gets enough light.
Black Sooty Mold
When this mold grows on your Schefflera, the leaves will appear to have ash coating.
Sooty mold is specifically a plant mold. It grows well in the secretions pests (aphids, scale) produce.
Remove the pests that are the underlying cause before removing the mold itself.
Once the pests are gone, you can proceed to wash off all the sooty mold parts.
Tip: Neem oil works great at removing both pests and fungi.
Overwatering plants is a common issue among growers. It’s good to give your Schefflera a generous amount of water, but ensure that you don’t overdo it.
If your Schefflera is suffering from overwatering, the leaves will turn black before falling off.
Feel the soil before watering it by dipping your finger into the soil, up to your knuckle.
If the soil still feels wet, it doesn’t water yet. Watering once per week is enough.
If your Schefflera gets plenty of bright light or grows in full sunlight, you need to then give it more water.
Overdrying the Soil
Schefflera prefers moist soil. Letting the soil dry out too much means that the next time you water, the water isn’t going to thoroughly wet the soil.
Dry soil essentially causes dehydration. And thirsty plants show their pain by wilting and drying up. Leaves may look scorched, ie. black, because of the lack of water.
Keep the soil moist. Feel the soil to determine if it’s too dry or wet.
Lack of Nutrition
Some plants need a little extra help in the form of fertilizers, which provide key nutrients.
Leaves turning black could signify that your Schefflera is lacking something.
SRFs and liquid fertilizers are excellent choices to use on Schefflera plants.
What’s more, high fertilizer levels (roughly one-and-a-half teaspoons of Osmocote 19-6-12 per four-inch container) showed a huge reduction in Alternaria, Pseudomonas, and Xanthomonas leaf spot diseases. (Source: University of Florida)
Like overwatering, overfertilizing is a big problem. Flooding your Schefflera with an abundance of nutrients can result in burned leaves that may appear black. The salt buildup also occurs with overfertilizing.
Read the label instructions carefully on when and how often to fertilize. Remember that the less light your Schefflera gets, the less fertilization it requires and vice versa.
This disease, caused by several pathogens that either weaken or kill seedlings during the germination process.
Organisms including Rhizoctonia, Pythium, Alternaria, Phytophthora, and Fusarium are responsible for this disease, which favors wet, cool conditions.
Seedling diseases decrease the quality of mature plants. So, if your Schefflera contracted a damping-off disease as a seedling, it would now be susceptible to a range of problems.
Sadly, there isn’t a cure for plants that contracted damping-off as a seedling.
How to Prevent Blackening of Schefflera Leaves
If you’ve gotten this far, you now know the best ways to prevent Schefflera leaves from turning that dreaded black color. Below are pointing to keep in mind.
- Make sure your Schefflera receives medium to bright light.
- Avoid prolonged periods of direct, severe sunlight to prevent sunburn.
- Temperature should always be above 50°F (10°C) to prevent cold damage.
- Keep your Schefflera in an area where there are no drafts.
- Don’t let your Schefflera sit in water; empty the drainage plate of any excess.
- Let soil dry out between waterings.
- Don’t let the soil get too alkaline – avoid using fresh manure, lime, and ash.
- Keep foliage relatively dry, gentle misting is good.
- Prune away any yellow, brown, or black leaves to prevent attracting fungus gnats.
- Schefflera grow best in temperatures between 65°F – 90°F (18°C – 32°C).
If you follow the advice here, I assure you that your Schefflera will flourish. With good light, warm temperature, sufficient water, and a draft-free area, black leaves become a thing of the past.
I wish you and your Schefflera the best of luck on your journey ahead!