Poinsettias tend to flood the market over winter holidays, quickly claiming the title for “the best selling potted flowering plant” – and for good reasons. These plants produce brightly colored bracts or modified leaves that turn white, pink, or red over the holiday season.
As such, I understand your frustration if “disaster” has struck and you’ve been left wondering, “why are the leaves falling off my poinsettia?“
Why Are The Leaves Falling Off My Poinsettia
When the leaves of a poinsettia start falling off, most people make the mistake of believing it’s dead, and so they cast the whole plant away. In most cases, this is a mistake, so allow me to elaborate using the three main reasons below.
1. The Leaves Are Meant To Fall Off
I assure you that if you ask around, you’ll learn that even the most green-thumbed among us have suffered the loss of their poinsettia plants that were gifted to them for Christmas. So, why is it so common for leaves to fall of poinsettia trees after the holidays?
The reason is simple: the plants are big business. Millions of poinsettias are grown in giant nurseries throughout the year.
Worse yet, a huge portion of them is a little more than rooted cuttings that were subjected to lots of unnatural hours of darkness in order to force the red bracts to appear before they were then torn from these nursery beds and unceremoniously thrown into pots with a bit of soil so they can be shipped off to their markets.
With that in mind, this implies that the reason poinsettias look so amazing when you pick them off the supermarket shelves is that they are sold within a day of them being potted.
And as soon as they make it to the buyers’ home, they start looking miserable because they’re still in shock. That’s not even the whole story. Imagine this.
You’ve acquired the potted plant in December, and the weather is cold all across the northern hemisphere. So, you place it on the most focal point of your home so everyone who walks in can be left in awe. Shortly after that, however, you notice that the soil is getting a bit dry, so you water the plant.
What you do not know is that the chances of the plant receiving any of the water are slim since the roots aren’t sufficiently developed to get all the way down and consume it.
If you’re lucky, osmosis will try sucking up the water through the dry compost, but the chance of the plant receiving any of it remains slim, and as such, the thirst causes more leaves to start dropping.
Once January rolls in, the poinsettia’s remaining leaves start falling as well because these plants are deciduous and tend to lose all their leaves during winter.
2. What About Diseases?
Over the years I’ve spent learning everything I can about poinsettias, I’ve realized that one of the most common issues that plague the plant is a disease known in the scientific community as Alternaria leaf spot.
So if you’ve just acquired the plant, but it’s losing a whole lot of its leaves right away, this disease could be the culprit.
Let’s start with the signs.
The most common symptoms of a poinsettia plagued by Alternaria leaf spot disease are blackish and/or brown spots on the plant’s leaves.
These spots usually start tiny, but if the plant is left untreated, they grow out to the leaf’s full size. In the most advanced stage, the disease causes your poinsettia’s leaves to start falling off en-mass.
Also worth noting is this disease isn’t necessarily deadly to the plant. But if you let it run its course, expect your plant to die off eventually.
Regarding the best way to deal with Alternaria leaf spot, the essential thing to do is get rid of any affected leaves the moment you notice the affliction. Since fungi are responsible for this disease, the spots can spread further if left untreated, so a lot of pruning should be expected.
Once you’ve adequately pruned the poinsettia, prevent any further growth by spraying the rest of the tree using a fungicidal spray.
Over the next couple of weeks, continue monitoring the poinsettia, as resurgents are common when dealing with Alternaria leaf spot.
If you notice more spots popping up, prune the tree again, and spray more fungicide. That said, be careful with the fungicide since too much of it could be toxic to your plant.
The general rule of thumb is to hold off any spraying activities three to five days before another spray session.
3. Poor Environmental Conditions
Another common cause of leaves falling off of your poinsettia is drastic changes in temperature levels either in the airflow or around the plant. This is particularly true if you’ve just brought your poinsettia home from a nursery, where it was grown under entirely different conditions.
To prevent this, try emulating the temperature, watering sessions, light, and humidity levels the tree was used to in the greenhouse.
As for the temperature, always keep it above 55 degrees F. Pick the warmest space in your home for the plant, and make sure there are no vents or drafts nearby, as these can unstabilize the temperature in the airflow and cause the leaves to fall off your poinsettia.
What’s more? Poinsettias aren’t fans of direct sunlight, so ensure the space you’ve chosen gets bright, indirect light. If the poinsettia was grown in the pot you purchased it in, ensuring that it stays sufficiently watered should prevent the leaves from falling off. Only water it when the top inch of the soil is dry.
No one said owning a poinsettia isn’t going to be hard; they only said it would be worth it. Going the extra mile should help your poinsettia maintain its stunning looks throughout the holiday season.
That said, expect the plant’s leaves to start falling off as the holidays draw to a close. That’s normal and shouldn’t leave you wondering, “why are the leaves falling off my poinsettia?”