There’s a tonne of information out there about why your Pothos leaves might be turning yellow, but barely anything on why your Pothos stem might be turning yellow.
There are a few reasons this could be happening – for one thing, some Pothos just get yellower stems as they grow, especially if the amount of variegation increases.
I used to have what I thought was a jade Pothos, and as it got older, the stems changed from green to cream.
Turns out it was a golden Pothos that liked the light it was in and started putting out more variegated leaves.
This is very much a best-case scenario though.
Often yellow stems on Pothos can be a sign that there’s something amiss.
Luckily, Pothos are both very forgiving and easy to propagate so there's a high chance we can rescue them, regardless of how far gone they are.
Only once the stems are brown and either mushy or dried out, are they beyond help.
Stem rot
Stem rot rarely happens in isolation.
There’s usually some sign that there’s an issue on the leaves – if there are black marks or yellowing, usually starting in the older leaves, that can be a sign that there’s rot somewhere.
There are a few things that lead to root rot, but they all result in a lack of oxygen to the roots, which creates a lovely environment for bacteria to flourish.
Check for:
- Overwatering. Pothos like to dry out before they’re watered, so only water when the soil is dry. Use a moisture metre if you’re unsure.
- Too big of a pot. The soil stays wet for too long because it can hold far more water than the plant can use
- Too dense of a soil mix. again, the soil can hold more water than the plant can use, plus there are fewer air pockets.
There are other things that can cause stem rot, but these are the main three.
Too big of a pot is more common than you might think. You only need a pot slightly bigger than the size of the root ball regardless of the size of the plant.
Sunburn/bleaching
Just like the leaves, Pothos stems can burn and bleach in the sun.
In the case of burn, you may need to chop and prop the stems, because if the stem is dead, the leaves are no longer connected to the roots.
The stem will eventually go brown when it's completely dead, so you can wait until that happens to take cuttings.
The stem may just be bleached by the sun.
Whilst it’s not great for the plant, it’s not as serious as being burnt, especially when it’s just the stem.
When the leaves are bleached though, it reduces the amount of chlorophyll in the leaves so the plant can’t photosynthesise as well.
I don’t have a bleached pothos, but I did put my Philodendron Squamiferum under a grow light that was a little too strong for it:
Pothos can take a lot of light (and it’s the only way to get those big, fenestrated leaves) BUT it can cause bleaching in the older leaves. If you have new leaves coming in thick and fast, then your Pothos is probably fine where it is. If there’s limited new growth and the old growth is bleached, I would move it into the shade.
The bleached leaves are more sensitive to being burned, so putting them in a shadier spot and gradually increasing the light (so the plant has a chance to produce chemicals that protect it from the sun) is a good idea.
Variegation
Sometimes Pothos stems just go yellow. It happened to me:
The stem on the left is much yellower than the one on the right, even though they’re from the same plant. They’re just coming in yellower as the plant gets more variegated.
Overwatering
I’ve already covered this. Don’t know why I gave it its own section.
Here are a few articles on overwatering you might enjoy:
How long does it take a plant to recover from overwatering?
Why do waterlogged plants die?
12 signs that a plant is overwatered
It’s reached the end of its life
As with leaves, sometimes stems get old and stop growing. I will say, this tends to happen when the plant has either had a pretty hard life or when it’s been moved to a position that doesn’t suit it as well as where it was before.
This happens a lot with plants we buy from the garden centre.
They’re kept in great conditions (hopefully) and grow really full and bushy.
When we bring them home, our home environment might not be quite as good, which leads to some stems/vines being, shall we say, terminated by the plant.
It's not necessarily a sign that something's wrong, just that the plant can't sustain that particular stem. It's reached its capacity!
In the plant pictured above, it’s actually the petiole that’s turned yellow – the actual stem is fine. The leaf is, er, not though, and will need removing before it attracts every fungus gnat in northern England.
It’s searching for more light
I don’t know if this is caused by the plant itself, or if it’s an optical illusion caused by the stretched-out vine (and the fact more of the vine is visible). I suppose it could also be paler because it’s more exposed.
ANYWAY
When plants don’t get enough light, they grow longer, thinner stems and petioles, so they can stretch towards the light. In the houseplant space, we call it leggy, but I’m struggling to refer to that as a technical term.
I could say 'longer internodal space' but leggy is easier. Spindly growth is also popular, but the word spindly gives me the creeps.
Regardless, it can make the stems look yellow. The only real solution is to give the plant more light, but just be aware that dramatically increasing the light suddenly can cause burning, so do it gradually.
By the way, some plants (mainly Hoya) send out vines/runners as a matter of course. That’s just how they grow:
Pothos don’t do this, so if the internodal spacing (the space on the stem between the leaves) is large, increase the light if you can.
Pests
Certain pests (mealybugs, thrips, spider mites, aphids) literally suck the juices out of your plant’s leaves which can cause them to go yellow over time.
In the case of bad infestations, the yellow tinge can also appear on the Pothos’ stems too.
In general, sick, stressed, houseplants take on a yellowish tinge all over. Much like we do!
How to work out why your Pothos stems are yellow
There’s no easy way to diagnose problems with your Pothos.
If only.
Plants only display a couple of different symptoms, and it's up to us to work out why they're doing it. I know it's frustrating, but the only thing you can do is work through the possible causes and cross them off as you go along.
The benefit of doing this is that everything you do will benefit your plant. For example, your Pothos stems may be yellowing because there are a few thrips on it but incidentally, the pot is also too big.
Whilst that’s not causing an issue now, it may do in the future, so repotting is still in the best interests of the plant even if it won’t help the current problem.
Top tip: start by cleaning off your plant's leaves. It helps with light absorption, it clears stomata so they perform gas exchange better, and you're removing a decent proportion of any pests.
Final thoughts
Yellowing stems on Pothos can be caused by a number of issues, from overwatering to pests. Pothos are pretty resilient, so if you make sure their roots can breathe (but remain well hydrated), give them plenty of light, and keep them clear of pests, they’re likely to make a full recovery.
And you can always chop and prop if the stem is rotten or the roots are past repair.
