Rubber trees, rubber figs, rubber plants, whatever you call Ficus elastica, there’s one thing we can all agree on and that’s how impressive the foliage is.
The huge, glossy leaves make a big impact and if you have one of the variegated types, they’re even more distinctive.
So when one or more of the leaves start to turn yellow, it’s very obvious.
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There are a number of reasons the foliage might change color and it’s important to figure out what’s causing the problem so you can fix it.
In our guide to growing rubber trees, we cover how to cultivate these popular houseplants.
If you’re seeing yellow leaves, this guide will go over the top seven reasons why this may happen and what to do about it to solve your rubber tree woes.
Here’s what I’ll cover:
Why Rubber Tree Foliage Turns Yellow
This is completely anecdotal, but I have problems with my rubber tree dropping leaves far more often than with it developing yellow foliage.
If you find that’s the case for you, read our guide to rubber trees dropping their leaves for some tips. Many of the causes of leaf drop are the same that you’ll find here.
With that out of the way, let’s talk about the problem that plagues us all, plant and human alike.
1. Aging
If all of the other leaves on your plant look fine but a couple of the bottom ones are turning yellow and drooping a little, it might just be the age of the leaf.
Make sure you check the soil moisture and other causes on this list, but if everything seems as it should be, it’s probably the leaf turning yellow as it ages.
As with many plants, when the older foliage matures, it dies and drops off.
As long as it’s just one or two leaves here and there and new healthy foliage is developing, it’s nothing to stress about.
In the same vein, if you move a plant from one area to a distinctly different area, say from a sunny spot to a darker spot, the plant might drop a few lower leaves as it adjusts.
2. Disease
I have two words for you: root rot. This goes hand-in-hand with overwatering.
We’ll talk in more detail about root rot later in this article as it can be caused by pathogens or by simply drowning the roots in too much water, but it should be treated the same in either case.
Bacterial leaf spot, caused by the bacterial pathogen Xanthomonas campestris, causes the leaves between the veins to turn yellow as it advances, though it starts as yellow spots on the foliage.
If your plant is infected with bacterial leaf spot, the only course of action is to remove the symptomatic leaves and support the plant by ensuring it’s not overcrowded, watering appropriately, and taking steps to reduce humidity.
There is no cure for this disease so if more than half of the plant is symptomatic, it’s probably best to dispose of it.
3. Overwatering
Overwatering is one of the biggest problems that plague our houseplants.
Most of us are guilty of providing too much water at times, I know I’ve killed my fair share of plants before I figured it out!
With rubber figs, you can let the top inch of soil dry out between waterings. Too much moisture will lead to root rot which will cause the leaves to turn yellow.
Usually, they will turn pale yellow and might even develop mushy brown spots. Then, the leaves will drop. If the rot continues, the plant will likely die.
The first piece of advice I always give people is to stop watering on a schedule.
I know it’s easy to make a note on your your calendar to water on a particular day, but a plant’s moisture needs vary from week to week depending on the weather, the amount of light hitting the foliage, the compaction of the soil, how much your HVAC is running, the time of year, and more.
All of these factors are constantly changing, so you can’t just assume that because the calendar says so, it’s time to water.
Feel the soil or use a soil moisture meter to determine when it’s time to water. It doesn’t take more than a few seconds more and your rubber fig will thank you.
If the roots are constantly sitting in excess water, they can’t take up nutrients from the soil – essentially drowning – which leads to root rot.
If you suspect root rot, remove the plant from its container and prune off any dead or mushy roots before spraying them with copper fungicide.
Then, soak the soil every two weeks with copper fungicide to kill off any pathogens.
If your rubber tree is growing in the ground, leave it in place and just use a soil soak.
Copper fungicide is a must-have in any gardening toolkit because you can use it to treat so many different diseases.
Bonide Copper Fungicide
Pick some up at Arbico Organics in a 32-ounce ready-to-use, 16- or 32-ounce hose end, or 16-ounce concentrate.
4. Pests
All of the usual sapsucking suspects can cause yellowing foliage, and usually, it’s in the form of stippling rather than a uniform discoloration.
Aphids, mealybugs, scale, and spider mites are all potential problems.
Examine your plant closely for evidence of pests. Look for webbing, lumps, fuzzy growth, or the actual insects themselves.
On houseplants, most pests can be managed by spraying them off with a strong stream of lukewarm water once a week or so.
You can alternate this with a treatment with insecticidal soap.
Good old insecticidal soap is generally safe for plants and targets most of the pests commonly seen on houseplants.
Bonide Insecticidal Soap
You can find Bonide insecticidal soap available at Arbico Organics in 12- or 32-ounce bottles.
Scale insects can be wiped with isopropyl alcohol and gently scraped off with a butter knife.
Although rare in houseplants, outdoor rubber figs can be attacked by foliar nematodes.
These microscopic worms in the Aphelenchoides genus cause the areas between the veins to turn yellow.
They thrive in areas with high humidity and when the plant has persistently wet foliage from overhead watering.
5. Too Little Light
Rubber figs are adaptable. In their natural habitat, they grow in hot, humid climates in full sun.
In our homes, they make do with low humidity and little sun. But you can only push them so far before they start to suffer.
In too much shade or darkness, the foliage will become pale and yellow. This tends to happen throughout the plant and not just on one or two of the leaves.
If you aren’t sure whether your plant is receiving enough light, you can always grab yourself a light meter.
Often, you can find light meters that are combined with a soil moisture meter.
This four-in-one meter from the Raintrip Store via Amazon tests soil moisture, light, pH, and the three major macronutrients.
Four-in-One Light, Moisture, pH, and Nutrient Meter
If you determine that your plant needs more light, you can introduce your plant to an hour or two of additional light with no problem, but if you need to move it to a location with four or more hours of light than it currently receives, do it gradually.
Place it in a sunnier spot for 30 minutes and then move it back to its old location for the rest of the day.
The next day, make it an hour before you move back, and so on. This helps to prevent the plant becoming stressed and potentially dropping its leaves.
6. Too Much Sun
As mentioned, rubber figs are capable of growing in full sun in their native environments. But most of the specimens that we grow indoors aren’t used to that kind of exposure.
If you were to take a rubber fig from a dark bathroom and plop it outside in full sun, you can bet you’ll see some leaf yellowing and probably some dropping foliage, as well.
I once had a rubber tree that was a few feet away from a nice, sunny window.
I didn’t move it, but I installed a mirror on the wall across from it and that mirror reflected the sun. Suddenly, I realized that some of the leaves of my plant had tannish-yellow spots on them.
When I looked closer, I realized that all the discoloration was on the same side and only on the uppermost leaves.
That’s when the lightbulb went off in my brain, and I realized what was happening. I had inadvertently given my plant more light than it was used to, and too quickly!
If you’re going to introduce your houseplant to bright sunshine, it’s a process that needs to be done gradually, as mentioned above. And watch for those mirrors and other reflective surfaces!
7. Underwatering
Low humidity and low soil moisture will inevitably cause the foliage to turn yellow and fall off the plant. It often starts with the lower leaves.
While the symptoms can look similar to overwatering, you can check the moisture with your finger or a moisture meter. If underwatering is the problem, the leaves won’t turn brown or mushy, they’ll be yellowish and dry.
Rubber trees like moderate humidity, somewhere between 40 and 60 percent. If it drops too far below this, the plant will protest by dropping leaves. Too much above this and you run the risk of disease problems.
Similarly, if the soil is allowed to dry out repeatedly, the leaves will turn yellow and fall.
Be sure to stay on top of watering and add more whenever the top inch or so dries out. If low humidity is the problem, you can raise the moisture levels in the air by grouping plants together, keeping your rubber fig in a kitchen or bathroom, or using a little humidifier nearby.
Things like spraying the leaves or putting the plant on a pebble tray filled with water won’t provide enough humidity to do the job.
If you live in a very dry region, you can find super convenient humidifiers that are quiet and go for a long time.
Levoit Humidifier
Something like the LEVOIT 2.5-liter tank humidifier would be perfect. Pick one up at Amazon in white or black and with or without a nightlight.
Green is Gold
Rubber trees might drop a leaf here and there, but they’re pretty resilient plants. Figure out what’s going wrong with them, fix it, and they’ll be back to normal in no time.
What is causing the yellow leaves on your rubber plant? Not sure? Let us know in the comments and maybe we can help you figure it out.
And for more information about growing Ficus plants, add these guides to your reading list next:
